U.S. patent application number 13/031539 was filed with the patent office on 2011-08-11 for use of micro-electro-mechanical systems (mems) in well treatments.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES, INC.. Invention is credited to Gary Frisch, Gordon Moake, Krishna M. Ravi, Craig W. RODDY.
Application Number | 20110192598 13/031539 |
Document ID | / |
Family ID | 44352767 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110192598 |
Kind Code |
A1 |
RODDY; Craig W. ; et
al. |
August 11, 2011 |
Use of Micro-Electro-Mechanical Systems (MEMS) in Well
Treatments
Abstract
A method of servicing a wellbore, comprising placing a plurality
of Micro-Electro-Mechanical System (MEMS) sensors in at least a
portion of a sealant composition, placing the sealant composition
in an annular space formed between a casing and the wellbore wall,
and monitoring, via the MEMS sensors, the sealant composition
and/or the annular space for a presence of gas, water, or both. A
method of servicing a wellbore, comprising placing a plurality of
Micro-Electro-Mechanical System (MEMS) sensors in a wellbore
composition, placing the wellbore composition in the wellbore, and
monitoring, via the MEMS sensors, the wellbore and/or the
surrounding formation for movement.
Inventors: |
RODDY; Craig W.; (Duncan,
OK) ; Ravi; Krishna M.; (Kingwood, TX) ;
Frisch; Gary; (Houston, TX) ; Moake; Gordon;
(Houston, TX) |
Assignee: |
HALLIBURTON ENERGY SERVICES,
INC.
Houston
TX
|
Family ID: |
44352767 |
Appl. No.: |
13/031539 |
Filed: |
February 21, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12618067 |
Nov 13, 2009 |
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13031539 |
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11695329 |
Apr 2, 2007 |
7712527 |
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12618067 |
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Current U.S.
Class: |
166/253.1 ;
166/250.04; 166/254.1 |
Current CPC
Class: |
E21B 33/13 20130101;
E21B 47/13 20200501; E21B 47/01 20130101; E21B 47/10 20130101; E21B
47/005 20200501; E21B 43/25 20130101 |
Class at
Publication: |
166/253.1 ;
166/250.04; 166/254.1 |
International
Class: |
E21B 47/00 20060101
E21B047/00; E21B 47/09 20060101 E21B047/09 |
Claims
1. A method of servicing a wellbore, comprising: placing a
plurality of Micro-Electro-Mechanical System (MEMS) sensors in at
least a portion of a sealant composition; placing the sealant
composition in an annular space formed between a casing and the
wellbore wall; and monitoring, via the MEMS sensors, the sealant
composition and/or the annular space for a presence of gas, water,
or both.
2. The method of claim 1, wherein the sealant composition is a
cement slurry and wherein the monitoring is carried out prior to
setting of the cement slurry.
3. The method of claim 2, further comprising signaling an operator
upon detection of gas and/or water.
4. The method of claim 2, further comprising providing a location
in the wellbore corresponding a detection of gas and/or water.
5. The method of claim 3, further comprising applying pressure to
the well upon detection of gas and/or water.
6. The method of claim 3, further comprising activating at least
one device to prevent flow out of the well upon detection gas
and/or water.
7. The method of claim 2, wherein the cement slurry is pumped down
the annulus in a reverse cementing service.
8. The method of claim 2, wherein the cement slurry is pumped down
the casing and up the annulus in a conventional cementing
service.
9. The method of claim 1, wherein the sealant composition is a
cement slurry and wherein the monitoring is carried out after
setting of the cement slurry.
10. The method of claim 9, wherein the monitoring is carried out by
running an interrogator tool into the wellbore at one or more
service intervals over the operating life of the well.
11. The method of claim 9, further comprising providing a location
in the wellbore corresponding a detection of gas and/or water.
12. The method of claim 11, further comprising assessing the
integrity of the casing and/or the cement proximate the location
where gas and/or water is detected.
13. The method of claim 12, further comprising performing a
remedial action on the casing and/or the cement proximate the
location where gas and/or water is detected.
14. The method of claim 13, wherein the remedial action comprises
placing additional sealant composition proximate the location where
gas and/or water is detected.
15. The method of claim 13, wherein the remedial action comprises
replacing and/or reinforcing the casing proximate the location
where gas and/or water is detected.
16. The method of claim 9, further comprising upon detection of gas
and/or water, adjusting an operating condition of the well.
17. The method of claim 16, wherein the operating condition
comprises temperature, pressure, production rate, length of service
interval, or any combination thereof.
18. The method of claim 16, wherein adjusting the operating
condition extends an expected service life of the wellbore.
19. A method of servicing a wellbore, comprising: placing a
plurality of Micro-Electro-Mechanical System (MEMS) sensors in a
wellbore composition; placing the wellbore composition in the
wellbore; and monitoring, via the MEMS sensors, the wellbore and/or
the surrounding formation for movement.
20. The method of claim 19, wherein the MEMS sensors are in a
sealant composition placed within an annular casing space in the
wellbore and wherein the movement comprises a relative movement
between the sealant composition and the adjacent casing and/or
wellbore wall.
21. The method of claim 19, wherein at least a portion of the
wellbore composition comprising the MEMS flows into the surrounding
formation and wherein the movement comprises a movement in the
formation.
22. The method of claim 21, further comprising upon detection of
the movement in the formation, adjusting an operating condition of
the well.
23. The method of claim 22, wherein the operating condition
comprises a production rate of the wellbore.
24. The method of claim 23, wherein adjusting the production rate
extends an expected service life of the wellbore.
25. The method of claim 1, wherein the gas comprises carbon
dioxide, hydrogen sulfide, or combinations thereof.
26. The method of claim 12, wherein a corrosive gas is
detected.
27. The method of claim 12, wherein the integrity of the casing
and/or cement is compromised via corrosion and further comprising
performing a remedial action on the casing and/or the cement
proximate the location where corrosion is present.
28. The method of claim 1, wherein the wellbore is associated with
a carbon dioxide injection system and wherein the monitoring an
undesirable leak or loss of zonal isolation in the wellbore.
29. The method of claim 28, further comprising performing a
remedial action on the casing and/or the cement proximate a
location where the leak or loss of zonal isolation is detected.
30. The method of claim 29, further comprising placing carbon
dioxide into the wellbore and surrounding formation to sequester
the carbon dioxide.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part application of U.S. patent
application Ser. No. 12/618,067 filed on Nov. 13, 2009, published
as U.S. Patent Application Publication No. 2010/0051266 A1, which
is a continuation-in-part application of U.S. patent application
Ser. No. 11/695,329, now U.S. Pat. No. 7,712,527, both entitled
"Use of Micro-Electro-Mechanical Systems (MEMS) in Well
Treatments," each of which is hereby incorporated by reference
herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This disclosure relates to the field of drilling,
completing, servicing, and treating a subterranean well such as a
hydrocarbon recovery well. In particular, the present disclosure
relates to systems and methods for detecting and/or monitoring the
position and/or condition of a wellbore, the surrounding formation,
and/or wellbore compositions, for example wellbore sealants such as
cement, using MEMS-based data sensors. Still more particularly, the
present disclosure describes systems and methods of monitoring the
integrity and performance of the wellbore, the surrounding
formation and/or the wellbore compositions from drilling/completion
through the life of the well using MEMS-based data sensors.
[0004] 2. Background of the Invention
[0005] Natural resources such as gas, oil, and water residing in a
subterranean formation or zone are usually recovered by drilling a
wellbore into the subterranean formation while circulating a
drilling fluid in the wellbore. After terminating the circulation
of the drilling fluid, a string of pipe (e.g., casing) is run in
the wellbore. The drilling fluid is then usually circulated
downward through the interior of the pipe and upward through the
annulus, which is located between the exterior of the pipe and the
walls of the wellbore. Next, primary cementing is typically
performed whereby a cement slurry is placed in the annulus and
permitted to set into a hard mass (i.e., sheath) to thereby attach
the string of pipe to the walls of the wellbore and seal the
annulus. Subsequent secondary cementing operations may also be
performed. One example of a secondary cementing operation is
squeeze cementing whereby a cement slurry is employed to plug and
seal off undesirable flow passages in the cement sheath and/or the
casing. Non-cementitious sealants are also utilized in preparing a
wellbore. For example, polymer, resin, or latex-based sealants may
be desirable for placement behind casing.
[0006] To enhance the life of the well and minimize costs, sealant
slurries are chosen based on calculated stresses and
characteristics of the formation to be serviced. Suitable sealants
are selected based on the conditions that are expected to be
encountered during the sealant service life. Once a sealant is
chosen, it is desirable to monitor and/or evaluate the health of
the sealant so that timely maintenance can be performed and the
service life maximized. The integrity of sealant can be adversely
affected by conditions in the well. For example, cracks in cement
may allow water influx while acid conditions may degrade cement.
The initial strength and the service life of cement can be
significantly affected by the water content and the slurry
formulation. Water content, slurry formulation and temperature are
the primary drivers for the hydration of cement slurries. Thus, it
is desirable to measure one or more sealant parameters (e.g.,
moisture content, temperature, pH and ion concentration) in order
to monitor sealant integrity.
[0007] Active, embeddable sensors can involve drawbacks that make
them undesirable for use in a wellbore environment. For example,
low-powered (e.g., nanowatt) electronic moisture sensors are
available, but have inherent limitations when embedded within
cement. The highly alkali environment can damage their electronics,
and they are sensitive to electromagnetic noise. Additionally,
power must be provided from an internal battery to activate the
sensor and transmit data, which increases sensor size and decreases
useful life of the sensor. Accordingly, an ongoing need exists for
improved methods of monitoring wellbore sealant condition from
placement through the service lifetime of the sealant.
[0008] Likewise, in performing wellbore servicing operations, an
ongoing need exists for improvements related to monitoring and/or
detecting a condition and/or location of a wellbore, formation,
wellbore servicing tool, wellbore servicing fluid, or combinations
thereof. Such needs may be meet by the novel and inventive systems
and methods for use of MEMS sensors down hole in accordance with
the various embodiments described herein.
BRIEF SUMMARY
[0009] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in at least a portion of a sealant composition,
placing the sealant composition in an annular space formed between
a casing and the wellbore wall, and monitoring, via the MEMS
sensors, the sealant composition and/or the annular space for a
presence of gas, water, or both.
[0010] Further disclosed herein is a method of servicing a
wellbore, comprising placing a plurality of
Micro-Electro-Mechanical System (MEMS) sensors in a wellbore
composition, placing the wellbore composition in the wellbore, and
monitoring, via the MEMS sensors, the wellbore and/or the
surrounding formation for movement.
[0011] The foregoing has outlined rather broadly the features and
technical advantages of the present disclosure in order that the
detailed description that follows may be better understood.
Additional features and advantages of the apparatus and method will
be described hereinafter that form the subject of the claims of
this disclosure. It should be appreciated by those skilled in the
art that the conception and the specific embodiments disclosed may
be readily utilized as a basis for modifying or designing other
structures for carrying out the same purposes of the present
disclosure. It should also be realized by those skilled in the art
that such equivalent constructions do not depart from the spirit
and scope of the apparatus and method as set forth in the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] For a detailed description of the embodiments of the
apparatus and methods of the present disclosure, reference will now
be made to the accompanying drawing in which:
[0013] FIG. 1 is a flowchart illustrating an embodiment of a method
in accordance with the present disclosure.
[0014] FIG. 2 is a schematic view of a typical onshore oil or gas
drilling rig and wellbore.
[0015] FIG. 3 is a flowchart detailing a method for determining
when a reverse cementing operation is complete and for subsequent
optional activation of a downhole tool.
[0016] FIG. 4 is a flowchart of a method for selecting between a
group of sealant compositions according to one embodiment of the
present disclosure.
[0017] FIGS. 5, 6, 7, 8, 9, 10 are schematic views of embodiments
of a wellbore parameter sensing system.
[0018] FIGS. 11 and 12 flowcharts of methods for servicing a
wellbore.
[0019] FIG. 13 is a schematic cross-sectional view of an embodiment
of a casing.
[0020] FIGS. 14 and 15 are schematic views of further embodiments
of a wellbore parameter sensing system.
[0021] FIG. 16 is a flowchart of a method for servicing a
wellbore.
[0022] FIG. 17 is a schematic view of a portion of a wellbore.
[0023] FIGS. 18a to 18c are schematic cross-sectional views at
different elevations of the wellbore of FIG. 17.
[0024] FIG. 19 is a schematic view of a portion of a wellbore.
[0025] FIGS. 20a to 20e are schematic cross-sectional views at
different elevations of the wellbore of FIG. 19.
[0026] FIG. 21 is a flowchart of a method for servicing a
wellbore.
[0027] FIGS. 22a to 22c are schematic views of a further embodiment
of a wellbore parameter sensing system.
[0028] FIGS. 23a to 23c are schematic views of a further embodiment
of a wellbore parameter sensing system.
[0029] FIGS. 23d to 23f are flowcharts of methods for servicing a
wellbore.
[0030] FIGS. 24a to 24c are schematic views of embodiments of a
wellbore parameter sensing system.
[0031] FIG. 24d is a flowchart of a method for servicing a
wellbore.
[0032] FIG. 25 is a schematic view of a further embodiment of a
wellbore parameter sensing system.
[0033] FIGS. 26a to 26c are schematic cross-sectional views at
different elevations of the wellbore of FIG. 25.
[0034] FIG. 26d is a flowchart of a method for servicing a
wellbore.
[0035] FIGS. 27a, 28a, 29a, 30a, and 31 are schematic views of
embodiments of a wellbore parameter sensing system.
[0036] FIGS. 27b, 28b, 29b, and 30b are flowcharts of methods for
servicing a wellbore.
[0037] FIGS. 32 and 35 are schematic views of embodiments of a
downhole interrogation/communication unit.
[0038] FIGS. 33 and 34 are schematic views of embodiment of a
downhole power generator.
DETAILED DESCRIPTION
[0039] Disclosed herein are methods for detecting and/or monitoring
the position and/or condition of a wellbore, a formation, a
wellbore service tool, and/or wellbore compositions, for example
wellbore sealants such as cement, using MEMS-based data sensors.
Still more particularly, the present disclosure describes methods
of monitoring the integrity and performance of wellbore
compositions over the life of the well using MEMS-based data
sensors. Performance may be indicated by changes, for example, in
various parameters, including, but not limited to, moisture
content, temperature, pH, and various ion concentrations (e.g.,
sodium, chloride, and potassium ions) of the cement. In
embodiments, the methods comprise the use of embeddable data
sensors capable of detecting parameters in a wellbore composition,
for example a sealant such as cement. In embodiments, the methods
provide for evaluation of sealant during mixing, placement, and/or
curing of the sealant within the wellbore. In another embodiment,
the method is used for sealant evaluation from placement and curing
throughout its useful service life, and where applicable to a
period of deterioration and repair. In embodiments, the methods of
this disclosure may be used to prolong the service life of the
sealant, lower costs, and enhance creation of improved methods of
remediation. Additionally, methods are disclosed for determining
the location of sealant within a wellbore, such as for determining
the location of a cement slurry during primary cementing of a
wellbore as discussed further hereinbelow. Additional embodiments
and methods for employing MEMS-based data sensors in a wellbore are
described herein.
[0040] The methods disclosed herein comprise the use of various
wellbore compositions, including sealants and other wellbore
servicing fluids. As used herein, "wellbore composition" includes
any composition that may be prepared or otherwise provided at the
surface and placed down the wellbore, typically by pumping. As used
herein, a "sealant" refers to a fluid used to secure components
within a wellbore or to plug or seal a void space within the
wellbore. Sealants, and in particular cement slurries and
non-cementitious compositions, are used as wellbore compositions in
several embodiments described herein, and it is to be understood
that the methods described herein are applicable for use with other
wellbore compositions. As used herein, "servicing fluid" refers to
a fluid used to drill, complete, work over, fracture, repair,
treat, or in any way prepare or service a wellbore for the recovery
of materials residing in a subterranean formation penetrated by the
wellbore. Examples of servicing fluids include, but are not limited
to, cement slurries, non-cementitious sealants, drilling fluids or
muds, spacer fluids, fracturing fluids or completion fluids, all of
which are well known in the art. While fluid is generally
understood to encompass material in a pumpable state, reference to
a wellbore servicing fluid that is settable or curable (e.g., a
sealant such as cement) includes, unless otherwise noted, the fluid
in a pumpable and/or set state, as would be understood in the
context of a given wellbore servicing operation. Generally,
wellbore servicing fluid and wellbore composition may be used
interchangeably unless otherwise noted. The servicing fluid is for
use in a wellbore that penetrates a subterranean formation. It is
to be understood that "subterranean formation" encompasses both
areas below exposed earth and areas below earth covered by water
such as ocean or fresh water. The wellbore may be a substantially
vertical wellbore and/or may contain one or more lateral wellbores,
for example as produced via directional drilling. As used herein,
components are referred to as being "integrated" if they are formed
on a common support structure placed in packaging of relatively
small size, or otherwise assembled in close proximity to one
another.
[0041] Discussion of an embodiment of the method of the present
disclosure will now be made with reference to the flowchart of FIG.
1, which includes methods of placing MEMS sensors in a wellbore and
gathering data. At block 100, data sensors are selected based on
the parameter(s) or other conditions to be determined or sensed
within the wellbore. At block 102, a quantity of data sensors is
mixed with a wellbore composition, for example a sealant slurry. In
embodiments, data sensors are added to a sealant by any methods
known to those of skill in the art. For example, the sensors may be
mixed with a dry material, mixed with one more liquid components
(e.g., water or a non-aqueous fluid), or combinations thereof. The
mixing may occur onsite, for example addition of the sensors into a
bulk mixer such as a cement slurry mixer. The sensors may be added
directly to the mixer, may be added to one or more component
streams and subsequently fed to the mixer, may be added downstream
of the mixer, or combinations thereof. In embodiments, data sensors
are added after a blending unit and slurry pump, for example,
through a lateral by-pass. The sensors may be metered in and mixed
at the well site, or may be pre-mixed into the composition (or one
or more components thereof) and subsequently transported to the
well site. For example, the sensors may be dry mixed with dry
cement and transported to the well site where a cement slurry is
formed comprising the sensors. Alternatively or additionally, the
sensors may be pre-mixed with one or more liquid components (e.g.,
mix water) and transported to the well site where a cement slurry
is formed comprising the sensors. The properties of the wellbore
composition or components thereof may be such that the sensors
distributed or dispersed therein do not substantially settle during
transport or placement.
[0042] The wellbore composition, e.g., sealant slurry, is then
pumped downhole at block 104, whereby the sensors are positioned
within the wellbore. For example, the sensors may extend along all
or a portion of the length of the wellbore adjacent the casing. The
sealant slurry may be placed downhole as part of a primary
cementing, secondary cementing, or other sealant operation as
described in more detail herein. At block 106, a data interrogation
tool (also referred to as a data interrogator tool, data
interrogator, interrogator, interrogation/communication tool or
unit, or the like) is positioned in an operable location to gather
data from the sensors, for example lowered or otherwise placed
within the wellbore proximate the sensors. In various embodiments,
one or more data interrogators may be placed downhole (e.g., in a
wellbore) prior to, concurrent with, and/or subsequent to placement
in the wellbore of a wellbore composition comprising MEMS sensors.
At block 108, the data interrogation tool interrogates the data
sensors (e.g., by sending out an RF signal) while the data
interrogation tool traverses all or a portion of the wellbore
containing the sensors. The data sensors are activated to record
and/or transmit data at block 110 via the signal from the data
interrogation tool. At block 112, the data interrogation tool
communicates the data to one or more computer components (e.g.,
memory and/or microprocessor) that may be located within the tool,
at the surface, or both. The data may be used locally or remotely
from the tool to calculate the location of each data sensor and
correlate the measured parameter(s) to such locations to evaluate
sealant performance. Accordingly, the data interrogation tool
comprises MEMS sensor interrogation functionality, communication
functionality (e.g., transceiver functionality), or both.
[0043] Data gathering, as shown in blocks 106 to 112 of FIG. 1, may
be carried out at the time of initial placement in the well of the
wellbore composition comprising MEMS sensors, for example during
drilling (e.g., drilling fluid comprising MEMS sensors) or during
cementing (e.g., cement slurry comprising MEMS sensors) as
described in more detail below. Additionally or alternatively, data
gathering may be carried out at one or more times subsequent to the
initial placement in the well of the wellbore composition
comprising MEMS sensors. For example, data gathering may be carried
out at the time of initial placement in the well of the wellbore
composition comprising MEMS sensors or shortly thereafter to
provide a baseline data set. As the well is operated for recovery
of natural resources over a period of time, data gathering may be
performed additional times, for example at regular maintenance
intervals such as every 1 year, 5 years, or 10 years. The data
recovered during subsequent monitoring intervals can be compared to
the baseline data as well as any other data obtained from previous
monitoring intervals, and such comparisons may indicate the overall
condition of the wellbore. For example, changes in one or more
sensed parameters may indicate one or more problems in the
wellbore. Alternatively, consistency or uniformity in sensed
parameters may indicate no substantive problems in the wellbore.
The data may comprise any combination of parameters sensed by the
MEMS sensors as present in the wellbore, including but not limited
to temperature, pressure, ion concentration, stress, strain, gas
concentration, etc. In an embodiment, data regarding performance of
a sealant composition includes cement slurry properties such as
density, rate of strength development, thickening time, fluid loss,
and hydration properties; plasticity parameters; compressive
strength; shrinkage and expansion characteristics; mechanical
properties such as Young's Modulus and Poisson's ratio; tensile
strength; resistance to ambient conditions downhole such as
temperature and chemicals present; or any combination thereof, and
such data may be evaluated to determine long term performance of
the sealant composition (e.g., detect an occurrence of radial
cracks, shear failure, and/or de-bonding within the set sealant
composition) in accordance with embodiments set forth in K. Ravi
and H. Xenakis, "Cementing Process Optimized to Achieve Zonal
Isolation," presented at PETROTECH-2007 Conference, New Delhi,
India, which is incorporated herein by reference in its entirety.
In an embodiment, data (e.g., sealant parameters) from a plurality
of monitoring intervals is plotted over a period of time, and a
resultant graph is provided showing an operating or trend line for
the sensed parameters. Atypical changes in the graph as indicated
for example by a sharp change in slope or a step change on the
graph may provide an indication of one or more present problems or
the potential for a future problem. Accordingly, remedial and/or
preventive treatments or services may be applied to the wellbore to
address present or potential problems.
[0044] In embodiments, the MEMS sensors are contained within a
sealant composition placed substantially within the annular space
between a casing and the wellbore wall. That is, substantially all
of the MEMS sensors are located within or in close proximity to the
annular space. In an embodiment, the wellbore servicing fluid
comprising the MEMS sensors (and thus likewise the MEMS sensors)
does not substantially penetrate, migrate, or travel into the
formation from the wellbore. In an alternative embodiment,
substantially all of the MEMS sensors are located within, adjacent
to, or in close proximity to the wellbore, for example less than or
equal to about 1 foot, 3 feet, 5 feet, or 10 feet from the
wellbore. Such adjacent or close proximity positioning of the MEMS
sensors with respect to the wellbore is in contrast to placing MEMS
sensors in a fluid that is pumped into the formation in large
volumes and substantially penetrates, migrates, or travels into or
through the formation, for example as occurs with a fracturing
fluid or a flooding fluid. Thus, in embodiments, the MEMS sensors
are placed proximate or adjacent to the wellbore (in contrast to
the formation at large), and provide information relevant to the
wellbore itself and compositions (e.g., sealants) used therein
(again in contrast to the formation or a producing zone at large).
In alternative embodiments, the MEMS sensors are distributed from
the wellbore into the surrounding formation (e.g., additionally or
alternatively non-proximate or non-adjacent to the wellbore), for
example as a component of a fracturing fluid or a flooding fluid
described in more detail herein.
[0045] In embodiments, the sealant is any wellbore sealant known in
the art. Examples of sealants include cementitious and
non-cementitious sealants both of which are well known in the art.
In embodiments, non-cementitious sealants comprise resin based
systems, latex based systems, or combinations thereof. In
embodiments, the sealant comprises a cement slurry with
styrene-butadiene latex (e.g., as disclosed in U.S. Pat. No.
5,588,488 incorporated by reference herein in its entirety).
Sealants may be utilized in setting expandable casing, which is
further described hereinbelow. In other embodiments, the sealant is
a cement utilized for primary or secondary wellbore cementing
operations, as discussed further hereinbelow.
[0046] In embodiments, the sealant is cementitious and comprises a
hydraulic cement that sets and hardens by reaction with water.
Examples of hydraulic cements include but are not limited to
Portland cements (e.g., classes A, B, C, G, and H Portland
cements), pozzolana cements, gypsum cements, phosphate cements,
high alumina content cements, silica cements, high alkalinity
cements, shale cements, acid/base cements, magnesia cements, fly
ash cement, zeolite cement systems, cement kiln dust cement
systems, slag cements, micro-fine cement, metakaolin, and
combinations thereof. Examples of sealants are disclosed in U.S.
Pat. Nos. 6,457,524; 7,077,203; and 7,174,962, each of which is
incorporated herein by reference in its entirety. In an embodiment,
the sealant comprises a sorel cement composition, which typically
comprises magnesium oxide and a chloride or phosphate salt which
together form for example magnesium oxychloride. Examples of
magnesium oxychloride sealants are disclosed in U.S. Pat. Nos.
6,664,215 and 7,044,222, each of which is incorporated herein by
reference in its entirety.
[0047] The wellbore composition (e.g., sealant) may include a
sufficient amount of water to form a pumpable slurry. The water may
be fresh water or salt water (e.g., an unsaturated aqueous salt
solution or a saturated aqueous salt solution such as brine or
seawater). In embodiments, the cement slurry may be a lightweight
cement slurry containing foam (e.g., foamed cement) and/or hollow
beads/microspheres. In an embodiment, the MEMS sensors are
incorporated into or attached to all or a portion of the hollow
microspheres. Thus, the MEMS sensors may be dispersed within the
cement along with the microspheres. Examples of sealants containing
microspheres are disclosed in U.S. Pat. Nos. 4,234,344; 6,457,524;
and 7,174,962, each of which is incorporated herein by reference in
its entirety. In an embodiment, the MEMS sensors are incorporated
into a foamed cement such as those described in more detail in U.S.
Pat. Nos. 6,063,738; 6,367,550; 6,547,871; and 7,174,962, each of
which is incorporated by reference herein in its entirety.
[0048] In some embodiments, additives may be included in the cement
composition for improving or changing the properties thereof.
Examples of such additives include but are not limited to
accelerators, set retarders, defoamers, fluid loss agents,
weighting materials, dispersants, density-reducing agents,
formation conditioning agents, lost circulation materials,
thixotropic agents, suspension aids, or combinations thereof. Other
mechanical property modifying additives, for example, fibers,
polymers, resins, latexes, and the like can be added to further
modify the mechanical properties. These additives may be included
singularly or in combination. Methods for introducing these
additives and their effective amounts are known to one of ordinary
skill in the art.
[0049] In embodiments, the MEMS sensors are contained within a
wellbore composition that forms a filtercake on the face of the
formation when placed downhole. For example, various types of
drilling fluids, also known as muds or drill-in fluids have been
used in well drilling, such as water-based fluids, oil-based fluids
(e.g., mineral oil, hydrocarbons, synthetic oils, esters, etc.),
gaseous fluids, or a combination thereof. Drilling fluids typically
contain suspended solids. Drilling fluids may form a thin, slick
filter cake on the formation face that provides for successful
drilling of the wellbore and helps prevent loss of fluid to the
subterranean formation. In an embodiment, at least a portion of the
MEMS remain associated with the filtercake (e.g., disposed therein)
and may provide information as to a condition (e.g., thickness)
and/or location of the filtercake. Additionally or in the
alternative at least a portion of the MEMS remain associated with
drilling fluid and may provide information as to a condition and/or
location of the drilling fluid.
[0050] In embodiments, the MEMS sensors are contained within a
wellbore composition that when placed downhole under suitable
conditions induces fractures within the subterranean formation.
Hydrocarbon-producing wells often are stimulated by hydraulic
fracturing operations, wherein a fracturing fluid may be introduced
into a portion of a subterranean formation penetrated by a wellbore
at a hydraulic pressure sufficient to create, enhance, and/or
extend at least one fracture therein. Stimulating or treating the
wellbore in such ways increases hydrocarbon production from the
well. In some embodiments, the MEMS sensors may be contained within
a wellbore composition that when placed downhole enters and/or
resides within one or more fractures within the subterranean
formation. In such embodiments, the MEMS sensors provide
information as to the location and/or condition of the fluid and/or
fracture during and/or after treatment. In an embodiment, at least
a portion of the MEMS remain associated with a fracturing fluid and
may provide information as to the condition and/or location of the
fluid. Fracturing fluids often contain proppants that are deposited
within the formation upon placement of the fracturing fluid
therein, and in an embodiment a fracturing fluid contains one or
more proppants and one or more MEMS. In an embodiment, at least a
portion of the MEMS remain associated with the proppants deposited
within the formation (e.g., a proppant bed) and may provide
information as to the condition (e.g., thickness, density,
settling, stratification, integrity, etc.) and/or location of the
proppants. Additionally or in the alternative at least a portion of
the MEMS remain associated with a fracture (e.g., adhere to and/or
retained by a surface of a fracture) and may provide information as
to the condition (e.g., length, volume, etc.) and/or location of
the fracture. For example, the MEMS sensors may provide information
useful for ascertaining the fracture complexity.
[0051] In embodiments, the MEMS sensors are contained in a wellbore
composition (e.g., gravel pack fluid) which is employed in a gravel
packing treatment, and the MEMS may provide information as to the
condition and/or location of the wellbore composition during and/or
after the gravel packing treatment. Gravel packing treatments are
used, inter alia, to reduce the migration of unconsolidated
formation particulates into the wellbore. In gravel packing
operations, particulates, referred to as gravel, are carried to a
wellbore in a subterranean producing zone by a servicing fluid
known as carrier fluid. That is, the particulates are suspended in
a carrier fluid, which may be viscosified, and the carrier fluid is
pumped into a wellbore in which the gravel pack is to be placed. As
the particulates are placed in the zone, the carrier fluid leaks
off into the subterranean zone and/or is returned to the surface.
The resultant gravel pack acts as a filter to separate formation
solids from produced fluids while permitting the produced fluids to
flow into and through the wellbore. When installing the gravel
pack, the gravel is carried to the formation in the form of a
slurry by mixing the gravel with a viscosified carrier fluid. Such
gravel packs may be used to stabilize a formation while causing
minimal impairment to well productivity. The gravel, inter alia,
acts to prevent the particulates from occluding the screen or
migrating with the produced fluids, and the screen, inter alia,
acts to prevent the gravel from entering the wellbore. In an
embodiment, the wellbore servicing composition (e.g., gravel pack
fluid) comprises a carrier fluid, gravel and one or more MEMS. In
an embodiment, at least a portion of the MEMS remain associated
with the gravel deposited within the wellbore and/or formation
(e.g., a gravel pack/bed) and may provide information as to the
condition (e.g., thickness, density, settling, stratification,
integrity, etc.) and/or location of the gravel pack/bed.
[0052] In various embodiments, the MEMS may provide information as
to a location, flow path/profile, volume, density, temperature,
pressure, or a combination thereof of a sealant composition, a
drilling fluid, a fracturing fluid, a gravel pack fluid, or other
wellbore servicing fluid in real time such that the effectiveness
of such service may be monitored and/or adjusted during performance
of the service to improve the result of same. Accordingly, the MEMS
may aid in the initial performance of the wellbore service
additionally or alternatively to providing a means for monitoring a
wellbore condition or performance of the service over a period of
time (e.g., over a servicing interval and/or over the life of the
well). For example, the one or more MEMS sensors may be used in
monitoring a gas or a liquid produced from the subterranean
formation. MEMS present in the wellbore and/or formation may be
used to provide information as to the condition (e.g., temperature,
pressure, flow rate, composition, etc.) and/or location of a gas or
liquid produced from the subterranean formation. In an embodiment,
the MEMS provide information regarding the composition of a
produced gas or liquid. For example, the MEMS may be used to
monitor an amount of water produced in a hydrocarbon producing well
(e.g., amount of water present in hydrocarbon gas or liquid), an
amount of undesirable components or contaminants in a produced gas
or liquid (e.g., sulfur, carbon dioxide, hydrogen sulfide, etc.
present in hydrocarbon gas or liquid), or a combination
thereof.
[0053] In embodiments, the data sensors added to the wellbore
composition, e.g., sealant slurry, etc., are passive sensors that
do not require continuous power from a battery or an external
source in order to transmit real-time data. In embodiments, the
data sensors are micro-electromechanical systems (MEMS) comprising
one or more (and typically a plurality of) MEMS devices, referred
to herein as MEMS sensors. MEMS devices are well known, e.g., a
semiconductor device with mechanical features on the micrometer
scale. MEMS embody the integration of mechanical elements, sensors,
actuators, and electronics on a common substrate. In embodiments,
the substrate comprises silicon. MEMS elements include mechanical
elements which are movable by an input energy (electrical energy or
other type of energy). Using MEMS, a sensor may be designed to emit
a detectable signal based on a number of physical phenomena,
including thermal, biological, optical, chemical, and magnetic
effects or stimulation. MEMS devices are minute in size, have low
power requirements, are relatively inexpensive and are rugged, and
thus are well suited for use in wellbore servicing operations.
[0054] In embodiments, the MEMS sensors added to a wellbore
servicing fluid may be active sensors, for example powered by an
internal battery that is rechargeable or otherwise powered and/or
recharged by other downhole power sources such as heat
capture/transfer and/or fluid flow, as described in more detail
herein.
[0055] In embodiments, the data sensors comprise an active material
connected to (e.g., mounted within or mounted on the surface of) an
enclosure, the active material being liable to respond to a
wellbore parameter, and the active material being operably
connected to (e.g., in physical contact with, surrounding, or
coating) a capacitive MEMS element. In various embodiments, the
MEMS sensors sense one or more parameters within the wellbore. In
an embodiment, the parameter is temperature. Alternatively, the
parameter is pH. Alternatively, the parameter is moisture content.
Still alternatively, the parameter may be ion concentration (e.g.,
chloride, sodium, and/or potassium ions). The MEMS sensors may also
sense well cement characteristic data such as stress, strain, or
combinations thereof. In embodiments, the MEMS sensors of the
present disclosure may comprise active materials that respond to
two or more measurands. In such a way, two or more parameters may
be monitored.
[0056] In addition or in the alternative, a MEMS sensor
incorporated within one or more of the wellbore compositions
disclosed herein may provide information that allows a condition
(e.g., thickness, density, volume, settling, stratification, etc.)
and/or location of the composition within the subterranean
formation to be detected.
[0057] Suitable active materials, such as dielectric materials,
that respond in a predictable and stable manner to changes in
parameters over a long period may be identified according to
methods well known in the art, for example see, e.g., Ong, Zeng and
Grimes. "A Wireless, Passive Carbon Nanotube-based Gas Sensor,"
IEEE Sensors Journal, 2, 2, (2002) 82-88; Ong, Grimes, Robbins and
Singl, "Design and application of a wireless, passive,
resonant-circuit environmental monitoring sensor," Sensors and
Actuators A, 93 (2001) 33-43, each of which is incorporated by
reference herein in its entirety. MEMS sensors suitable for the
methods of the present disclosure that respond to various wellbore
parameters are disclosed in U.S. Pat. No. 7,038,470 B1 that is
incorporated herein by reference in its entirety.
[0058] In embodiments, the MEMS sensors are coupled with radio
frequency identification devices (RFIDs) and can thus detect and
transmit parameters and/or well cement characteristic data for
monitoring the cement during its service life. RFIDs combine a
microchip with an antenna (the RFID chip and the antenna are
collectively referred to as the "transponder" or the "tag"). The
antenna provides the RFID chip with power when exposed to a narrow
band, high frequency electromagnetic field from a transceiver. A
dipole antenna or a coil, depending on the operating frequency,
connected to the RFID chip, powers the transponder when current is
induced in the antenna by an RF signal from the transceiver's
antenna. Such a device can return a unique identification "ID"
number by modulating and re-radiating the radio frequency (RF)
wave. Passive RF tags are gaining widespread use due to their low
cost, indefinite life, simplicity, efficiency, ability to identify
parts at a distance without contact (tether-free information
transmission ability). These robust and tiny tags are attractive
from an environmental standpoint as they require no battery. The
MEMS sensor and RFID tag are preferably integrated into a single
component (e.g., chip or substrate), or may alternatively be
separate components operably coupled to each other. In an
embodiment, an integrated, passive MEMS/RFID sensor contains a data
sensing component, an optional memory, and an RFID antenna, whereby
excitation energy is received and powers up the sensor, thereby
sensing a present condition and/or accessing one or more stored
sensed conditions from memory and transmitting same via the RFID
antenna.
[0059] In embodiments, MEMS sensors having different RFID tags,
i.e., antennas that respond to RF waves of different frequencies
and power the RFID chip in response to exposure to RF waves of
different frequencies, may be added to different wellbore
compositions. Within the United States, commonly used operating
bands for RFID systems center on one of the three government
assigned frequencies: 125 kHz, 13.56 MHz or 2.45 GHz. A fourth
frequency, 27.125 MHz, has also been assigned. When the 2.45 GHz
carrier frequency is used, the range of an RFID chip can be many
meters. While this is useful for remote sensing, there may be
multiple transponders within the RF field. In order to prevent
these devices from interacting and garbling the data,
anti-collision schemes are used, as are known in the art. In
embodiments, the data sensors are integrated with local tracking
hardware to transmit their position as they flow within a wellbore
composition such as a sealant slurry.
[0060] The data sensors may form a network using wireless links to
neighboring data sensors and have location and positioning
capability through, for example, local positioning algorithms as
are known in the art. The sensors may organize themselves into a
network by listening to one another, therefore allowing
communication of signals from the farthest sensors towards the
sensors closest to the interrogator to allow uninterrupted
transmission and capture of data. In such embodiments, the
interrogator tool may not need to traverse the entire section of
the wellbore containing MEMS sensors in order to read data gathered
by such sensors. For example, the interrogator tool may only need
to be lowered about half-way along the vertical length of the
wellbore containing MEMS sensors. Alternatively, the interrogator
tool may be lowered vertically within the wellbore to a location
adjacent to a horizontal arm of a well, whereby MEMS sensors
located in the horizontal arm may be read without the need for the
interrogator tool to traverse the horizontal arm. Alternatively,
the interrogator tool may be used at or near the surface and read
the data gathered by the sensors distributed along all or a portion
of the wellbore. For example, sensors located a distance away from
the interrogator (e.g., at an opposite end of a length of casing or
tubing) may communicate via a network formed by the sensors as
described previously.
[0061] Generally, a communication distance between MEMS sensors
varies with a size and/or mass of the MEMS sensors. However, an
ability to suspend the MEMS sensors in a wellbore composition and
keep the MEMS sensors suspended in the wellbore composition for a
long period of time, which may be important for measuring various
parameters of a wellbore composition throughout a volume of the
wellbore composition, generally varies inversely with the size of
the MEMS sensors. Therefore, sensor communication distance
requirements may have to be adjusted in view of sensor
suspendability requirements. In addition, a communication frequency
of a MEMS sensor generally varies with the size and/or mass of the
MEMS sensor.
[0062] In embodiments, the MEMS sensors are ultra-small, e.g., 3
mm.sup.2, such that they are pumpable in a sealant slurry. In
embodiments, the MEMS device is approximately 0.01 mm.sup.2 to 1
mm.sup.2, alternatively 1 mm.sup.2 to 3 mm.sup.2, alternatively 3
mm.sup.2 to 5 mm.sup.2, or alternatively 5 mm.sup.2 to 10 mm.sup.2.
In embodiments, the data sensors are capable of providing data
throughout the cement service life. In embodiments, the data
sensors are capable of providing data for up to 100 years. In an
embodiment, the wellbore composition comprises an amount of MEMS
effective to measure one or more desired parameters. In various
embodiments, the wellbore composition comprises an effective amount
of MEMS such that sensed readings may be obtained at intervals of
about 1 foot, alternatively about 6 inches, or alternatively about
1 inch, along the portion of the wellbore containing the MEMS. In
an embodiment, the MEMS sensors may be present in the wellbore
composition in an amount of from about 0.001 to about 10 weight
percent. Alternatively, the MEMS may be present in the wellbore
composition in an amount of from about 0.01 to about 5 weight
percent. In embodiments, the sensors may have dimensions (e.g.,
diameters or other dimensions) that range from nanoscale, e.g.,
about 1 to 1000 nm (e.g., NEMS), to a micrometer range, e.g., about
1 to 1000 .mu.m (e.g., MEMS), or alternatively any size from about
1 nm to about 1 mm. In embodiments, the MEMS sensors may be present
in the wellbore composition in an amount of from about 5 volume
percent to about 30 volume percent.
[0063] In various embodiments, the size and/or amount of sensors
present in a wellbore composition (e.g., the sensor loading or
concentration) may be selected such that the resultant wellbore
servicing composition is readily pumpable without damaging the
sensors and/or without having the sensors undesirably settle out
(e.g., screen out) in the pumping equipment (e.g., pumps, conduits,
tanks, etc.) and/or upon placement in the wellbore. Also, the
concentration/loading of the sensors within the wellbore servicing
fluid may be selected to provide a sufficient average distance
between sensors to allow for networking of the sensors (e.g.,
daisy-chaining) in embodiments using such networks, as described in
more detail herein. For example, such distance may be a percentage
of the average communication distance for a given sensor type. By
way of example, a given sensor having a 2 inch communication range
in a given wellbore composition should be loaded into the wellbore
composition in an amount that the average distance between sensors
in less than 2 inches (e.g., less than 1.9, 1.8, 1.7, 1.6, 1.5,
1.4, 1.3, 1.2, 1.1, 1.0, etc. inches). The size of sensors and the
amount may be selected so that they are stable, do not float or
sink, in the well treating fluid. The size of the sensor could
range from nano size to microns. In some embodiments, the sensors
may be nanoelectromechanical systems (NEMS), MEMS, or combinations
thereof. Unless otherwise indicated herein, it should be understood
that any suitable micro and/or nano sized sensors or combinations
thereof may be employed. The embodiments disclosed herein should
not otherwise be limited by the specific type of micro and/or nano
sensor employed unless otherwise indicated or prescribed by the
functional requirements thereof, and specifically NEMS may be used
in addition to or in lieu of MEMS sensors in the various
embodiments disclosed herein.
[0064] In embodiments, the MEMS sensors comprise passive (remain
unpowered when not being interrogated) sensors energized by energy
radiated from a data interrogation tool. The data interrogation
tool may comprise an energy transceiver sending energy (e.g., radio
waves) to and receiving signals from the MEMS sensors and a
processor processing the received signals. The data interrogation
tool may further comprise a memory component, a communications
component, or both. The memory component may store raw and/or
processed data received from the MEMS sensors, and the
communications component may transmit raw data to the processor
and/or transmit processed data to another receiver, for example
located at the surface. The tool components (e.g., transceiver,
processor, memory component, and communications component) are
coupled together and in signal communication with each other.
[0065] In an embodiment, one or more of the data interrogator
components may be integrated into a tool or unit that is
temporarily or permanently placed downhole (e.g., a downhole
module), for example prior to, concurrent with, and/or subsequent
to placement of the MEMS sensors in the wellbore. In an embodiment,
a removable downhole module comprises a transceiver and a memory
component, and the downhole module is placed into the wellbore,
reads data from the MEMS sensors, stores the data in the memory
component, is removed from the wellbore, and the raw data is
accessed. Alternatively, the removable downhole module may have a
processor to process and store data in the memory component, which
is subsequently accessed at the surface when the tool is removed
from the wellbore. Alternatively, the removable downhole module may
have a communications component to transmit raw data to a processor
and/or transmit processed data to another receiver, for example
located at the surface. The communications component may
communicate via wired or wireless communications. For example, the
downhole component may communicate with a component or other node
on the surface via a network of MEMS sensors, or cable or other
communications/telemetry device such as a radio frequency,
electromagnetic telemetry device or an acoustic telemetry device.
The removable downhole component may be intermittently positioned
downhole via any suitable conveyance, for example wire-line, coiled
tubing, straight tubing, gravity, pumping, etc., to monitor
conditions at various times during the life of the well.
[0066] In embodiments, the data interrogation tool comprises a
permanent or semi-permanent downhole component that remains
downhole for extended periods of time. For example, a
semi-permanent downhole module may be retrieved and data downloaded
once every few months or years. Alternatively, a permanent downhole
module may remain in the well throughout the service life of well.
In an embodiment, a permanent or semi-permanent downhole module
comprises a transceiver and a memory component, and the downhole
module is placed into the wellbore, reads data from the MEMS
sensors, optionally stores the data in the memory component, and
transmits the read and optionally stored data to the surface.
Alternatively, the permanent or semi-permanent downhole module may
have a processor to process and sensed data into processed data,
which may be stored in memory and/or transmit to the surface. The
permanent or semi-permanent downhole module may have a
communications component to transmit raw data to a processor and/or
transmit processed data to another receiver, for example located at
the surface. The communications component may communicate via wired
or wireless communications. For example, the downhole component may
communicate with a component or other node on the surface via a
network of MEMS sensors, or a cable or other
communications/telemetry device such as a radio frequency,
electromagnetic telemetry device or an acoustic telemetry
device.
[0067] In embodiments, the data interrogation tool comprises an RF
energy source incorporated into its internal circuitry and the data
sensors are passively energized using an RF antenna, which picks up
energy from the RF energy source. In an embodiment, the data
interrogation tool is integrated with an RF transceiver. In
embodiments, the MEMS sensors (e.g., MEMS/RFID sensors) are
empowered and interrogated by the RF transceiver from a distance,
for example a distance of greater than 10 m, or alternatively from
the surface or from an adjacent offset well. In an embodiment, the
data interrogation tool traverses within a casing in the well and
reads MEMS sensors located in a wellbore servicing fluid or
composition, for example a sealant (e.g., cement) sheath
surrounding the casing, located in the annular space between the
casing and the wellbore wall. In embodiments, the interrogator
senses the MEMS sensors when in close proximity with the sensors,
typically via traversing a removable downhole component along a
length of the wellbore comprising the MEMS sensors. In an
embodiment, close proximity comprises a radial distance from a
point within the casing to a planar point within an annular space
between the casing and the wellbore. In embodiments, close
proximity comprises a distance of 0.1 m to 1 m. Alternatively,
close proximity comprises a distance of 1 m to 5 m. Alternatively,
close proximity comprises a distance of from 5 m to 10 m. In
embodiments, the transceiver interrogates the sensor with RF energy
at 125 kHz and close proximity comprises 0.1 m to 5 m.
Alternatively, the transceiver interrogates the sensor with RF
energy at 13.5 MHz and close proximity comprises 0.05 m to 0.5 m.
Alternatively, the transceiver interrogates the sensor with RF
energy at 915 MHz and close proximity comprises 0.03 m to 0.1 m.
Alternatively, the transceiver interrogates the sensor with RF
energy at 2.4 GHz and close proximity comprises 0.01 m to 0.05
m.
[0068] In embodiments, the MEMS sensors incorporated into wellbore
cement and used to collect data during and/or after cementing the
wellbore. The data interrogation tool may be positioned downhole
prior to and/or during cementing, for example integrated into a
component such as casing, casing attachment, plug, cement shoe, or
expanding device. Alternatively, the data interrogation tool is
positioned downhole upon completion of cementing, for example
conveyed downhole via wireline. The cementing methods disclosed
herein may optionally comprise the step of foaming the cement
composition using a gas such as nitrogen or air. The foamed cement
compositions may comprise a foaming surfactant and optionally a
foaming stabilizer. The MEMS sensors may be incorporated into a
sealant composition and placed downhole, for example during primary
cementing (e.g., conventional or reverse circulation cementing),
secondary cementing (e.g., squeeze cementing), or other sealing
operation (e.g., behind an expandable casing).
[0069] In primary cementing, cement is positioned in a wellbore to
isolate an adjacent portion of the subterranean formation and
provide support to an adjacent conduit (e.g., casing). The cement
forms a barrier that prevents fluids (e.g., water or hydrocarbons)
in the subterranean formation from migrating into adjacent zones or
other subterranean formations. In embodiments, the wellbore in
which the cement is positioned belongs to a horizontal or
multilateral wellbore configuration. It is to be understood that a
multilateral wellbore configuration includes at least two principal
wellbores connected by one or more ancillary wellbores.
[0070] FIG. 2, which shows a typical onshore oil or gas drilling
rig and wellbore, will be used to clarify the methods of the
present disclosure, with the understanding that the present
disclosure is likewise applicable to offshore rigs and wellbores.
Rig 12 is centered over a subterranean oil or gas formation 14
located below the earth's surface 16. Rig 12 includes a work deck
32 that supports a derrick 34. Derrick 34 supports a hoisting
apparatus 36 for raising and lowering pipe strings such as casing
20. Pump 30 is capable of pumping a variety of wellbore
compositions (e.g., drilling fluid or cement) into the well and
includes a pressure measurement device that provides a pressure
reading at the pump discharge. Wellbore 18 has been drilled through
the various earth strata, including formation 14. Upon completion
of wellbore drilling, casing 20 is often placed in the wellbore 18
to facilitate the production of oil and gas from the formation 14.
Casing 20 is a string of pipes that extends down wellbore 18,
through which oil and gas will eventually be extracted. A cement or
casing shoe 22 is typically attached to the end of the casing
string when the casing string is run into the wellbore. Casing shoe
22 guides casing 20 toward the center of the hole and minimizes
problems associated with hitting rock ledges or washouts in
wellbore 18 as the casing string is lowered into the well. Casing
shoe, 22, may be a guide shoe or a float shoe, and typically
comprises a tapered, often bullet-nosed piece of equipment found on
the bottom of casing string 20. Casing shoe, 22, may be a float
shoe fitted with an open bottom and a valve that serves to prevent
reverse flow, or U-tubing, of cement slurry from annulus 26 into
casing 20 as casing 20 is run into wellbore 18. The region between
casing 20 and the wall of wellbore 18 is known as the casing
annulus 26. To fill up casing annulus 26 and secure casing 20 in
place, casing 20 is usually "cemented" in wellbore 18, which is
referred to as "primary cementing." A data interrogation tool 40 is
shown in the wellbore 18.
[0071] In an embodiment, the method of this disclosure is used for
monitoring primary cement during and/or subsequent to a
conventional primary cementing operation. In this conventional
primary cementing embodiment, MEMS sensors are mixed into a cement
slurry, block 102 of FIG. 1, and the cement slurry is then pumped
down the inside of casing 20, block 104 of FIG. 1. As the slurry
reaches the bottom of casing 20, it flows out of casing 20 and into
casing annulus 26 between casing 20 and the wall of wellbore 18. As
cement slurry flows up annulus 26, it displaces any fluid in the
wellbore. To ensure no cement remains inside casing 20, devices
called "wipers" may be pumped by a wellbore servicing fluid (e.g.,
drilling mud) through casing 20 behind the cement. As described in
more detail herein, the wellbore servicing fluids such as the
cement slurry and/or wiper conveyance fluid (e.g., drilling mud)
may contain MEMS sensors which aid in detection and/or positioning
of the wellbore servicing fluid and/or a mechanical component such
as a wiper plug, casing shoe, etc. The wiper contacts the inside
surface of casing 20 and pushes any remaining cement out of casing
20. When cement slurry reaches the earth's surface 16, and annulus
26 is filled with slurry, pumping is terminated and the cement is
allowed to set. The MEMS sensors of the present disclosure may also
be used to determine one or more parameters during placement and/or
curing of the cement slurry. Also, the MEMS sensors of the present
disclosure may also be used to determine completion of the primary
cementing operation, as further discussed herein below.
[0072] Referring back to FIG. 1, during cementing, or subsequent
the setting of cement, a data interrogation tool may be positioned
in wellbore 18, as at block 106 of FIG. 1. For example, the wiper
may be equipped with a data interrogation tool and may read data
from the MEMS while being pumped downhole and transmit same to the
surface. Alternatively, an interrogator tool may be run into the
wellbore following completion of cementing a segment of casing, for
example as part of the drill string during resumed drilling
operations. Alternatively, the interrogator tool may be run
downhole via a wireline or other conveyance. The data interrogation
tool may then be signaled to interrogate the sensors (block 108 of
FIG. 1) whereby the sensors are activated to record and/or transmit
data, block 110 of FIG. 1. The data interrogation tool communicates
the data to a processor 112 whereby data sensor (and likewise
cement slurry) position and cement integrity may be determined via
analyzing sensed parameters for changes, trends, expected values,
etc. For example, such data may reveal conditions that may be
adverse to cement curing. The sensors may provide a temperature
profile over the length of the cement sheath, with a uniform
temperature profile likewise indicating a uniform cure (e.g.,
produced via heat of hydration of the cement during curing) or a
change in temperature might indicate the influx of formation fluid
(e.g., presence of water and/or hydrocarbons) that may degrade the
cement during the transition from slurry to set cement.
Alternatively, such data may indicate a zone of reduced, minimal,
or missing sensors, which would indicate a loss of cement
corresponding to the area (e.g., a loss/void zone or water
influx/washout). Such methods may be available with various cement
techniques described herein such as conventional or reverse primary
cementing.
[0073] Due to the high pressure at which the cement is pumped
during conventional primary cementing (pump down the casing and up
the annulus), fluid from the cement slurry may leak off into
existing low pressure zones traversed by the wellbore. This may
adversely affect the cement, and incur undesirable expense for
remedial cementing operations (e.g., squeeze cementing as discussed
hereinbelow) to position the cement in the annulus. Such leak off
may be detected via the present disclosure as described previously.
Additionally, conventional circulating cementing may be
time-consuming, and therefore relatively expensive, because cement
is pumped all the way down casing 20 and back up annulus 26.
[0074] One method of avoiding problems associated with conventional
primary cementing is to employ reverse circulation primary
cementing. Reverse circulation cementing is a term of art used to
describe a method where a cement slurry is pumped down casing
annulus 26 instead of into casing 20. The cement slurry displaces
any fluid as it is pumped down annulus 26. Fluid in the annulus is
forced down annulus 26, into casing 20 (along with any fluid in the
casing), and then back up to earth's surface 16. When reverse
circulation cementing, casing shoe 22 comprises a valve that is
adjusted to allow flow into casing 20 and then sealed after the
cementing operation is complete. Once slurry is pumped to the
bottom of casing 20 and fills annulus 26, pumping is terminated and
the cement is allowed to set in annulus 26. Examples of reverse
cementing applications are disclosed in U.S. Pat. Nos. 6,920,929
and 6,244,342, each of which is incorporated herein by reference in
its entirety.
[0075] In embodiments of the present disclosure, sealant slurries
comprising MEMS data sensors are pumped down the annulus in reverse
circulation applications, a data interrogator is located within the
wellbore (e.g., integrated into the casing shoe) and sealant
performance is monitored as described with respect to the
conventional primary sealing method disclosed hereinabove.
Additionally, the data sensors of the present disclosure may also
be used to determine completion of a reverse circulation operation,
as further discussed hereinbelow.
[0076] Secondary cementing within a wellbore may be carried out
subsequent to primary cementing operations. A common example of
secondary cementing is squeeze cementing wherein a sealant such as
a cement composition is forced under pressure into one or more
permeable zones within the wellbore to seal such zones. Examples of
such permeable zones include fissures, cracks, fractures, streaks,
flow channels, voids, high permeability streaks, annular voids, or
combinations thereof. The permeable zones may be present in the
cement column residing in the annulus, a wall of the conduit in the
wellbore, a microannulus between the cement column and the
subterranean formation, and/or a microannulus between the cement
column and the conduit. The sealant (e.g., secondary cement
composition) sets within the permeable zones, thereby forming a
hard mass to plug those zones and prevent fluid from passing
therethrough (i.e., prevents communication of fluids between the
wellbore and the formation via the permeable zone). Various
procedures that may be followed to use a sealant composition in a
wellbore are described in U.S. Pat. No. 5,346,012, which is
incorporated by reference herein in its entirety. In various
embodiments, a sealant composition comprising MEMS sensors is used
to repair holes, channels, voids, and microannuli in casing, cement
sheath, gravel packs, and the like as described in U.S. Pat. Nos.
5,121,795; 5,123,487; and 5,127,473, each of which is incorporated
by reference herein in its entirety.
[0077] In embodiments, the method of the present disclosure may be
employed in a secondary cementing operation. In these embodiments,
data sensors are mixed with a sealant composition (e.g., a
secondary cement slurry) at block 102 of FIG. 1 and subsequent or
during positioning and hardening of the cement, the sensors are
interrogated to monitor the performance of the secondary cement in
an analogous manner to the incorporation and monitoring of the data
sensors in primary cementing methods disclosed hereinabove. For
example, the MEMS sensors may be used to verify the location of the
secondary sealant, one or more properties of the secondary sealant,
that the secondary sealant is functioning properly and/or to
monitor its long-term integrity.
[0078] In embodiments, the methods of the present disclosure are
utilized for monitoring cementitious sealants (e.g., hydraulic
cement), non-cementitious (e.g., polymer, latex or resin systems),
or combinations thereof, which may be used in primary, secondary,
or other sealing applications. For example, expandable tubulars
such as pipe, pipe string, casing, liner, or the like are often
sealed in a subterranean formation. The expandable tubular (e.g.,
casing) is placed in the wellbore, a sealing composition is placed
into the wellbore, the expandable tubular is expanded, and the
sealing composition is allowed to set in the wellbore. For example,
after expandable casing is placed downhole, a mandrel may be run
through the casing to expand the casing diametrically, with
expansions up to 25% possible. The expandable tubular may be placed
in the wellbore before or after placing the sealing composition in
the wellbore. The expandable tubular may be expanded before,
during, or after the set of the sealing composition. When the
tubular is expanded during or after the set of the sealing
composition, resilient compositions will remain competent due to
their elasticity and compressibility. Additional tubulars may be
used to extend the wellbore into the subterranean formation below
the first tubular as is known to those of skill in the art. Sealant
compositions and methods of using the compositions with expandable
tubulars are disclosed in U.S. Pat. Nos. 6,722,433 and 7,040,404
and U.S. Pat. Pub. No. 2004/0167248, each of which is incorporated
by reference herein in its entirety. In expandable tubular
embodiments, the sealants may comprise compressible hydraulic
cement compositions and/or non-cementitious compositions.
[0079] Compressible hydraulic cement compositions have been
developed which remain competent (continue to support and seal the
pipe) when compressed, and such compositions may comprise MEMS
sensors. The sealant composition is placed in the annulus between
the wellbore and the pipe or pipe string, the sealant is allowed to
harden into an impermeable mass, and thereafter, the expandable
pipe or pipe string is expanded whereby the hardened sealant
composition is compressed. In embodiments, the compressible foamed
sealant composition comprises a hydraulic cement, a rubber latex, a
rubber latex stabilizer, a gas and a mixture of foaming and foam
stabilizing surfactants. Suitable hydraulic cements include, but
are not limited to, Portland cement and calcium aluminate
cement.
[0080] Often, non-cementitious resilient sealants with comparable
strength to cement, but greater elasticity and compressibility, are
required for cementing expandable casing. In embodiments, these
sealants comprise polymeric sealing compositions, and such
compositions may comprise MEMS sensors. In an embodiment, the
sealants composition comprises a polymer and a metal containing
compound. In embodiments, the polymer comprises copolymers,
terpolymers, and interpolymers. The metal-containing compounds may
comprise zinc, tin, iron, selenium magnesium, chromium, or cadmium.
The compounds may be in the form of an oxide, carboxylic acid salt,
a complex with dithiocarbamate ligand, or a complex with
mercaptobenzothiazole ligand. In embodiments, the sealant comprises
a mixture of latex, dithio carbamate, zinc oxide, and sulfur.
[0081] In embodiments, the methods of the present disclosure
comprise adding data sensors to a sealant to be used behind
expandable casing to monitor the integrity of the sealant upon
expansion of the casing and during the service life of the sealant.
In this embodiment, the sensors may comprise MEMS sensors capable
of measuring, for example, moisture and/or temperature change. If
the sealant develops cracks, water influx may thus be detected via
moisture and/or temperature indication.
[0082] In an embodiment, the MEMS sensor are added to one or more
wellbore servicing compositions used or placed downhole in drilling
or completing a monodiameter wellbore as disclosed in U.S. Pat. No.
7,066,284 and U.S. Pat. Pub. No. 2005/0241855, each of which is
incorporated by reference herein in its entirety. In an embodiment,
the MEMS sensors are included in a chemical casing composition used
in a monodiameter wellbore. In another embodiment, the MEMS sensors
are included in compositions (e.g., sealants) used to place
expandable casing or tubulars in a monodiameter wellbore. Examples
of chemical casings are disclosed in U.S. Pat. Nos. 6,702,044;
6,823,940; and 6,848,519, each of which is incorporated herein by
reference in its entirety.
[0083] In one embodiment, the MEMS sensors are used to gather data,
e.g., sealant data, and monitor the long-term integrity of the
wellbore composition, e.g., sealant composition, placed in a
wellbore, for example a wellbore for the recovery of natural
resources such as water or hydrocarbons or an injection well for
disposal or storage. In an embodiment, data/information gathered
and/or derived from MEMS sensors in a downhole wellbore composition
e.g., sealant composition, comprises at least a portion of the
input and/or output to into one or more calculators, simulations,
or models used to predict, select, and/or monitor the performance
of wellbore compositions e.g., sealant compositions, over the life
of a well. Such models and simulators may be used to select a
wellbore composition, e.g., sealant composition, comprising MEMS
for use in a wellbore. After placement in the wellbore, the MEMS
sensors may provide data that can be used to refine, recalibrate,
or correct the models and simulators. Furthermore, the MEMS sensors
can be used to monitor and record the downhole conditions that the
composition, e.g., sealant, is subjected to, and composition, e.g.,
sealant, performance may be correlated to such long term data to
provide an indication of problems or the potential for problems in
the same or different wellbores. In various embodiments, data
gathered from MEMS sensors is used to select a wellbore
composition, e.g., sealant composition, or otherwise evaluate or
monitor such sealants, as disclosed in U.S. Pat. Nos. 6,697,738;
6,922,637; and 7,133,778, each of which is incorporated by
reference herein in its entirety.
[0084] In an embodiment, the compositions and methodologies of this
disclosure are employed in an operating environment that generally
comprises a wellbore that penetrates a subterranean formation for
the purpose of recovering hydrocarbons, storing hydrocarbons,
injection of carbon dioxide, storage of carbon dioxide, disposal of
carbon dioxide, and the like, and the MEMS located downhole (e.g.,
within the wellbore and/or surrounding formation) may provide
information as to a condition and/or location of the composition
and/or the subterranean formation. For example, the MEMS may
provide information as to a location, flow path/profile, volume,
density, temperature, pressure, or a combination thereof of a
hydrocarbon (e.g., natural gas stored in a salt dome) or carbon
dioxide placed in a subterranean formation such that effectiveness
of the placement may be monitored and evaluated, for example
detecting leaks, determining remaining storage capacity in the
formation, etc. In some embodiments, the compositions of this
disclosure are employed in an enhanced oil recovery operation
wherein a wellbore that penetrates a subterranean formation may be
subjected to the injection of gases (e.g., carbon dioxide) so as to
improve hydrocarbon recovery from said wellbore, and the MEMS may
provide information as to a condition and/or location of the
composition and/or the subterranean formation. For example, the
MEMS may provide information as to a location, flow path/profile,
volume, density, temperature, pressure, or a combination thereof of
carbon dioxide used in a carbon dioxide flooding enhanced oil
recovery operation in real time such that the effectiveness of such
operation may be monitored and/or adjusted in real time during
performance of the operation to improve the result of same.
[0085] Referring to FIG. 4, a method 200 for selecting a sealant
(e.g., a cementing composition) for sealing a subterranean zone
penetrated by a wellbore according to the present embodiment
basically comprises determining a group of effective compositions
from a group of compositions given estimated conditions experienced
during the life of the well, and estimating the risk parameters for
each of the group of effective compositions. In an alternative
embodiment, actual measured conditions experienced during the life
of the well, in addition to or in lieu of the estimated conditions,
may be used. Such actual measured conditions may be obtained for
example via sealant compositions comprising MEMS sensors as
described herein. Effectiveness considerations include concerns
that the sealant composition be stable under downhole conditions of
pressure and temperature, resist downhole chemicals, and possess
the mechanical properties to withstand stresses from various
downhole operations to provide zonal isolation for the life of the
well.
[0086] In step 212, well input data for a particular well is
determined and/or specified. Well input data includes routinely
measurable or calculable parameters inherent in a well, including
vertical depth of the well, overburden gradient, pore pressure,
maximum and minimum horizontal stresses, hole size, casing outer
diameter, casing inner diameter, density of drilling fluid, desired
density of sealant slurry for pumping, density of completion fluid,
and top of sealant. As will be discussed in greater detail with
reference to step 214, the well can be computer modeled. In
modeling, the stress state in the well at the end of drilling, and
before the sealant slurry is pumped into the annular space, affects
the stress state for the interface boundary between the rock and
the sealant composition. Thus, the stress state in the rock with
the drilling fluid is evaluated, and properties of the rock such as
Young's modulus, Poisson's ratio, and yield parameters are used to
analyze the rock stress state. These terms and their methods of
determination are well known to those skilled in the art. It is
understood that well input data will vary between individual wells.
In an alternative embodiment, well input data includes data that is
obtained via sealant compositions comprising MEMS sensors as
described herein.
[0087] In step 214, the well events applicable to the well are
determined and/or specified. For example, cement hydration
(setting) is a well event. Other well events include pressure
testing, well completions, hydraulic fracturing, hydrocarbon
production, fluid injection, perforation, subsequent drilling,
formation movement as a result of producing hydrocarbons at high
rates from unconsolidated formation, and tectonic movement after
the sealant composition has been pumped in place. Well events
include those events that are certain to happen during the life of
the well, such as cement hydration, and those events that are
readily predicted to occur during the life of the well, given a
particular well's location, rock type, and other factors well known
in the art. In an embodiment, well events and data associated
therewith may be obtained via sealant compositions comprising MEMS
sensors as described herein.
[0088] Each well event is associated with a certain type of stress,
for example, cement hydration is associated with shrinkage,
pressure testing is associated with pressure, well completions,
hydraulic fracturing, and hydrocarbon production are associated
with pressure and temperature, fluid injection is associated with
temperature, formation movement is associated with load, and
perforation and subsequent drilling are associated with dynamic
load. As can be appreciated, each type of stress can be
characterized by an equation for the stress state (collectively
"well event stress states"), as described in more detail in U.S.
Pat. No. 7,133,778 which is incorporated herein by reference in its
entirety.
[0089] In step 216, the well input data, the well event stress
states, and the sealant data are used to determine the effect of
well events on the integrity of the sealant sheath during the life
of the well for each of the sealant compositions. The sealant
compositions that would be effective for sealing the subterranean
zone and their capacity from its elastic limit are determined. In
an alternative embodiment, the estimated effects over the life of
the well are compared to and/or corrected in comparison to
corresponding actual data gathered over the life of the well via
sealant compositions comprising MEMS sensors as described herein.
Step 216 concludes by determining which sealant compositions would
be effective in maintaining the integrity of the resulting cement
sheath for the life of the well.
[0090] In step 218, parameters for risk of sealant failure for the
effective sealant compositions are determined. For example, even
though a sealant composition is deemed effective, one sealant
composition may be more effective than another. In one embodiment,
the risk parameters are calculated as percentages of sealant
competency during the determination of effectiveness in step 216.
In an alternative embodiment, the risk parameters are compared to
and/or corrected in comparison to actual data gathered over the
life of the well via sealant compositions comprising MEMS sensors
as described herein.
[0091] Step 218 provides data that allows a user to perform a cost
benefit analysis. Due to the high cost of remedial operations, it
is important that an effective sealant composition is selected for
the conditions anticipated to be experienced during the life of the
well. It is understood that each of the sealant compositions has a
readily calculable monetary cost. Under certain conditions, several
sealant compositions may be equally efficacious, yet one may have
the added virtue of being less expensive. Thus, it should be used
to minimize costs. More commonly, one sealant composition will be
more efficacious, but also more expensive. Accordingly, in step
220, an effective sealant composition with acceptable risk
parameters is selected given the desired cost. Furthermore, the
overall results of steps 200-220 can be compared to actual data
that is obtained via sealant compositions comprising MEMS sensors
as described herein, and such data may be used to modify and/or
correct the inputs and/or outputs to the various steps 200-220 to
improve the accuracy of same.
[0092] As discussed above and with reference to FIG. 2, wipers are
often utilized during conventional primary cementing to force
cement slurry out of the casing. The wiper plug also serves another
purpose: typically, the end of a cementing operation is signaled
when the wiper plug contacts a restriction (e.g., casing shoe)
inside the casing 20 at the bottom of the string. When the plug
contacts the restriction, a sudden pressure increase at pump 30 is
registered. In this way, it can be determined when the cement has
been displaced from the casing 20 and fluid flow returning to the
surface via casing annulus 26 stops.
[0093] In reverse circulation cementing, it is also necessary to
correctly determine when cement slurry completely fills the annulus
26. Continuing to pump cement into annulus 26 after cement has
reached the far end of annulus 26 forces cement into the far end of
casing 20, which could incur lost time if cement must be drilled
out to continue drilling operations.
[0094] The methods disclosed herein may be utilized to determine
when cement slurry has been appropriately positioned downhole.
Furthermore, as discussed hereinbelow, the methods of the present
disclosure may additionally comprise using a MEMS sensor to actuate
a valve or other mechanical means to close and prevent cement from
entering the casing upon determination of completion of a cementing
operation.
[0095] The way in which the method of the present disclosure may be
used to signal when cement is appropriately positioned within
annulus 26 will now be described within the context of a reverse
circulation cementing operation. FIG. 3 is a flowchart of a method
for determining completion of a cementing operation and optionally
further actuating a downhole tool upon completion (or to initiate
completion) of the cementing operation. This description will
reference the flowchart of FIG. 3, as well as the wellbore
depiction of FIG. 2.
[0096] At block 130, a data interrogation tool as described
hereinabove is positioned at the far end of casing 20. In an
embodiment, the data interrogation tool is incorporated with or
adjacent to a casing shoe positioned at the bottom end of the
casing and in communication with operators at the surface. At block
132, MEMS sensors are added to a fluid (e.g., cement slurry, spacer
fluid, displacement fluid, etc.) to be pumped into annulus 26. At
block 134, cement slurry is pumped into annulus 26. In an
embodiment, MEMS sensors may be placed in substantially all of the
cement slurry pumped into the wellbore. In an alternative
embodiment, MEMS sensors may be placed in a leading plug or
otherwise placed in an initial portion of the cement to indicate a
leading edge of the cement slurry. In an embodiment, MEMS sensors
are placed in leading and trailing plugs to signal the beginning
and end of the cement slurry. While cement is continuously pumped
into annulus 26, at decision 136, the data interrogation tool is
attempting to detect whether the data sensors are in communicative
(e.g., close) proximity with the data interrogation tool. As long
as no data sensors are detected, the pumping of additional cement
into the annulus continues. When the data interrogation tool
detects the sensors at block 138 indicating that the leading edge
of the cement has reached the bottom of the casing, the
interrogator sends a signal to terminate pumping. The cement in the
annulus is allowed to set and form a substantially impermeable mass
which physically supports and positions the casing in the wellbore
and bonds the casing to the walls of the wellbore in block 148.
[0097] If the fluid of block 130 is the cement slurry, MEMS-based
data sensors are incorporated within the set cement, and parameters
of the cement (e.g., temperature, pressure, ion concentration,
stress, strain, etc.) can be monitored during placement and for the
duration of the service life of the cement according to methods
disclosed hereinabove. Alternatively, the data sensors may be added
to an interface fluid (e.g., spacer fluid or other fluid plug)
introduced into the annulus prior to and/or after introduction of
cement slurry into the annulus.
[0098] The method just described for determination of the
completion of a primary wellbore cementing operation may further
comprise the activation of a downhole tool. For example, at block
130, a valve or other tool may be operably associated with a data
interrogation tool at the far end of the casing. This valve may be
contained within float shoe 22, for example, as disclosed
hereinabove. Again, float shoe 22 may contain an integral data
interrogation tool, or may otherwise be coupled to a data
interrogation tool. For example, the data interrogation tool may be
positioned between casing 20 and float shoe 22. Following the
method previously described and blocks 132 to 136, pumping
continues as the data interrogation tool detects the presence or
absence of data sensors in close proximity to the interrogator tool
(dependent upon the specific method cementing method being
employed, e.g., reverse circulation, and the positioning of the
sensors within the cement flow). Upon detection of a determinative
presence or absence of sensors in close proximity indicating the
termination of the cement slurry, the data interrogation tool sends
a signal to actuate the tool (e.g., valve) at block 140. At block
142, the valve closes, sealing the casing and preventing cement
from entering the portion of casing string above the valve in a
reverse cementing operation. At block 144, the closing of the valve
at 142, causes an increase in back pressure that is detected at the
hydraulic pump 30. At block 146, pumping is discontinued, and
cement is allowed to set in the annulus at block 148. In
embodiments wherein data sensors have been incorporated throughout
the cement, parameters of the cement (and thus cement integrity)
can additionally be monitored during placement and for the duration
of the service life of the cement according to methods disclosed
hereinabove.
[0099] In embodiments, systems for sensing, communicating and
evaluating wellbore parameters may include the wellbore 18; the
casing 20 or other workstring, toolstring, production string,
tubular, coiled tubing, wireline, or any other physical structure
or conveyance extending downhole from the surface; MEMS sensors 52
that may be placed into the wellbore 18 and/or surrounding
formation 14, for example, via a wellbore servicing fluid; and a
device or plurality of devices for interrogating the MEMS sensors
52 to gather/collect data generated by the MEMS sensors 52, for
transmitting the data from the MEMS sensors 52 to the earth's
surface 16, for receiving communications and/or data to the earth's
surface, for processing the data, or any combination thereof,
referred to collectively herein a data interrogation/communication
units or in some instances as a data interrogator or data
interrogation tool. Unless otherwise specified, it is understood
that such devices as disclosed in the various embodiments herein
will have MEMS sensor interrogation functionality, communication
functionality (e.g., transceiver functionality), or both, as will
be apparent from the particular embodiments and associated context
disclosed herein. The wellbore servicing fluid comprising the MEMS
sensors 52 may comprise a drilling fluid, a spacer fluid, a
sealant, a fracturing fluid, a gravel pack fluid, a completion
fluid, or any other fluid placed downhole. In addition, the MEMS
sensors 52 may be configured to measure physical parameters such as
temperature, stress and strain, as well as chemical parameters such
as CO.sub.2 concentration, H.sub.2S concentration, CH.sub.4
concentration, moisture content, pH, Na.sup.+ concentration,
K.sup.+ concentration, and Cl.sup.- concentration. Various
embodiments described herein are directed to
interrogation/communication units that are dispersed or distributed
at intervals along a length of the casing 20 and form a
communication network for transmitting and/or receiving
communications to/from a location downhole and the surface, with
the further understanding that the interrogation/communication
units may be otherwise physically supported by a workstring,
toolstring, production string, tubular, coiled tubing, wireline, or
any other physical structure or conveyance extending downhole from
the surface.
[0100] Referring to FIG. 5, a schematic view of a wellbore
parameter sensing system 300 is illustrated. The wellbore parameter
sensing system 300 may comprise the wellbore 18, inside which the
casing 20 is positioned. In an embodiment, the wellbore parameter
sensing system 300 may comprise one or more (e.g., a plurality) of
data interrogation/communication units 310, which may be situated
on the casing 20 and spaced at regular or irregular intervals along
the casing 20. In embodiments, the data interrogation/communication
units 310 may be situated on or in casing collars that couple
casing joints together. For example, the
interrogation/communication units 310 may be located in side pocket
mandrels or other spaces/voids within the casing collar or casing
joint. In addition, the data interrogation/communication units 310
may be situated in an interior of the casing 20, on an exterior of
the casing 20, or both. In an embodiment, the data
interrogation/communication units 310a may be coupled to one
another by an electrical cable 320, which may run along an entire
length of the casing 20 up to the earth's surface (where they may
connect to other components such as a processor 330 and a power
source 340), and are configured to transmit data between the data
interrogation/communication units 310 and/or the earth's surface
(e.g., the processor 330), supply power from the power source 340
to the data interrogation/communication units 310, or both. In
alternative embodiments, all or a portion of the
interrogation/communication units 310b communicate wirelessly with
one another.
[0101] In an embodiment, the data interrogation/communication units
310 may be configured as regional data interrogation/communication
units 310, which may be spaced apart about every 5 m to 15 m along
the length of the casing 20, alternatively about every 8 m to 12 m
along the length of the casing 20, alternatively about every 10 m
along the length of the casing 20. Each regional data
interrogation/communication unit 310 may be configured to
interrogate, and receive data from, the MEMS sensors 52 in a
vicinity of the regional data interrogation/communication unit 310.
The vicinity of the regional data interrogation/communication unit
310 may be defined as an approximately cylindrical region extending
upward from the regional data interrogation/communication unit 310,
up to half a distance from the regional data
interrogation/communication unit 310 in question to a regional data
interrogation/communication unit 310 immediately uphole from the
regional data interrogation/communication unit 310 in question, and
extending downward from the regional data
interrogation/communication unit 310, up to half a distance from
the regional data interrogation/communication unit 310 in question
to a regional data interrogation/communication unit 310 immediately
downhole from the regional data interrogation/communication unit
310 in question. The approximately cylindrical region may also
extend outward from a centerline of the casing 20, past an outer
wall of the casing 20, past a wall of the wellbore 18, and about
0.05 m to 0.15 m, alternatively about 0.08 m to 0.12 m,
alternatively about 0.1 m, into a formation through which the
wellbore 18 passes. All or a portion of the regional data
interrogation/communication units 310 may communicate with each
other via wired communications (e.g., units 310a), wireless
communications (e.g., 310b), or both.
[0102] In an embodiment, each MEMS sensor 52 situated in the casing
20 and/or in the annulus and/or in the formation, as well as in the
vicinity of the regional data interrogation/communication unit 310,
may transmit data regarding one or more parameters sensed by the
MEMS sensor 52 directly to the regional data
interrogation/communication unit 310 in response to being
interrogated by the regional data interrogation/communication unit
310. In an embodiment, the MEMS sensors 52 in the vicinity of the
regional data interrogation/communication unit 310 may form
regional networks of MEMS sensors 52 (and in some embodiments, with
regional networks of MEMS sensors generally corresponding to and
communicating with one or more similarly designated regional data
interrogation/communication units 310) and transmit MEMS sensor
data inwards and/or outwards and/or upwards and/or downwards
through the casing 20 and/or through the annulus 26, to the
regional data interrogation/communication unit 310 via the regional
networks of MEMS sensors 52. The double arrows 312, 314 signify
transmission of sensor data via regional networks of MEMS sensors
52, and the single arrows 316, 318 signify transmission of sensor
data directly from one or more MEMS sensors to the regional data
interrogation/communication units 310.
[0103] In an embodiment, the MEMS sensors 52 (including a network
of MEMS sensors) may be passive sensors, i.e., may be powered, for
example, by bursts of electromagnetic radiation from the regional
data interrogation/communication units 310. In an embodiment, the
MEMS sensors 52 (including a network of MEMS sensors) may be active
sensors, i.e., powered by a battery or batteries situated in or on
the sensor 52. In an embodiment, batteries of the MEMS sensors 52
may be inductively rechargeable by the regional data
interrogation/communication units 310.
[0104] Referring to FIG. 6, a schematic view of a further
embodiment of a wellbore parameter sensing system 400 is
illustrated. The wellbore parameter sensing system 400 may comprise
the wellbore 18, inside which the casing 20 is situated. In an
embodiment, the wellbore parameter sensing system 400 further
comprises a processor 410 configured to receive and process sensor
data from MEMS sensors 52, which are situated in the wellbore 18
and are configured to measure at least one parameter inside the
wellbore 18.
[0105] The embodiment of wellbore parameter sensing system 400
differs from that of wellbore parameter sensing system 300
illustrated in FIG. 5, in that the wellbore sensing system 400 does
not comprise any data interrogation/communication units (or
comprises very few, for example one at the end of a casing string
such as in a cement shoe and/or a few spaced at lengthy intervals
in comparision to FIG. 5) for interrogating, and receiving sensor
data from, the MEMS sensors 52. Instead, the MEMS sensors 52,
which, in an embodiment, are powered by batteries (or otherwise are
powered by a downhole power source such as ambient conditions,
e.g., temperature, fluid flow, etc.) situated in the sensors 52,
are configured to form a global data transmission network of MEMS
sensors 52 (e.g., a "daisy-chain" network) extending along the
entire length of the wellbore 18. Accordingly, sensor data
generated by MEMS sensors 52 at all elevations of the wellbore 18
may be transmitted to neighboring MEMS sensors 52 and uphole along
the entire length of the wellbore 18 to the processor 410. Double
arrows 412, 414 denote transmission of sensor data between
neighboring MEMS sensors 52. Single arrows 416, 418 denote
transmission of sensor data up the wellbore 18 via the global
network of MEMS sensors 52, and single arrows 420, 422 denote
transmission of sensor data from the annulus 26 and the interior of
the casing 20 to the exterior of the wellbore 18, for example to a
processor 410 or other data capture, storage, or transmission
equipment.
[0106] In an embodiment, the MEMS sensors 52 are contained in a
wellbore servicing fluid placed in the wellbore 18 and are present
in the wellbore servicing fluid at a MEMS sensor loading sufficient
for reliable transmission of MEMS sensor data from the interior of
the wellbore 18 to the processor 410.
[0107] Referring to FIG. 7, a schematic view of an embodiment of a
wellbore parameter sensing system 500 is illustrated. The wellbore
parameter sensing system 500 may comprise the wellbore 18, inside
which the casing 20 is situated. In an embodiment, the wellbore
parameter sensing system 500 may comprise one or more data
interrogation/communication units 510a and/or 510b, which may be
situated on the casing 20. In embodiments, the data
interrogation/communication unit 510 may be situated on or in a
casing collar that couples casing joints together, at the end of a
casing string such as a casing shoe, or any other suitable support
location along a mechanical conveyance extending from the surface
into the wellbore. In addition, the data
interrogation/communication unit 510 may be situated in an interior
of the casing 20, on an exterior of the casing 20, or both. In an
embodiment, the data interrogation/communication unit 510 may be
situated part way, e.g., about midway, between a downhole end of
the wellbore 18 and an uphole end of the wellbore 18.
[0108] In an embodiment, the data interrogation/communication unit
510a may be powered by a power source 540, which is situated at an
exterior of the wellbore 18 and is connected to the data
interrogation/communication unit 510a by an electrical cable 520.
The electrical cable 520 may be situated in the annulus 26 in close
proximity to, or in contact with, an outer wall of the casing 20
and run along at least a portion of the length of the casing 20. In
an embodiment, the data interrogation/communication unit, e.g.,
unit 510b, is powered and/or communicates wirelessly.
[0109] In an embodiment, the wellbore parameter sensing system 500
may further comprise a processor 530, which is connected to the
data interrogation/communication unit 510a via the electrical cable
520 and is configured to receive MEMS sensor data from the data
interrogation/communication unit 510a and process the MEMS sensor
data. In an embodiment, the wellbore parameter sensing system 500
may further comprise a processor 530, which is wirelessly connected
to the data interrogation/communication unit 510b and is configured
to receive MEMS sensor data from the data
interrogation/communication unit 510b and process the MEMS sensor
data.
[0110] In an embodiment, the MEMS sensors 52 may be passive
sensors, i.e., may be powered, for example, by bursts of
electromagnetic radiation from the data interrogation/communication
unit 510. In an embodiment, the MEMS sensors 52 may be active
sensors, i.e., powered by a battery or batteries situated in or on
the sensor 52 or by other downhole power sources. In an embodiment,
batteries of the MEMS sensors 52 may be inductively
rechargeable.
[0111] In an embodiment, MEMS sensors 52 may be placed inside the
wellbore 18 via a wellbore servicing fluid. The MEMS sensors 52 are
configured to measure at least one wellbore parameter and transmit
sensor data regarding the at least one wellbore parameter to the
data interrogation/communication unit 510. As in the case of the
embodiment of the wellbore parameter sensing system 400 illustrated
in FIG. 6, the MEMS sensors 52 may transmit MEMS sensor data to
neighboring MEMS sensors 52, thereby forming data transmission
networks of MEMS sensors for the purpose of transmitting MEMS
sensor data from MEMS sensors 52 situated away from the data
interrogation/communication unit 510 to the data
interrogation/communication unit 510. However, in contrast to the
embodiment of the wellbore parameter sensing system 400 illustrated
in FIG. 6, the MEMS sensors 52 in the embodiment of the wellbore
parameter sensing system 500 illustrated in FIG. 7 may, in some
instances, not have to transmit MEMS sensor data along the entire
length of the wellbore 18, but rather only along a portion of the
length of the wellbore 18, for example to reach a given primary or
regional data interrogation/communication unit. Horizontal double
arrows 512, 514 denote transmission of sensor data between MEMS
sensors 52 situated in the annulus 26 and inside the casing 20,
downwardly oriented single arrows 516, 518 denote transmission of
sensor data downhole to the data interrogation/communication unit
510, and upwardly oriented single arrows 522, 524 denote
transmission of sensor data uphole to the data
interrogation/communication unit 510.
[0112] Referring to FIG. 8, a schematic view of an embodiment of a
wellbore parameter sensing system 600 is illustrated. The wellbore
parameter sensing system 600 may comprise the wellbore 18, inside
which the casing 20 is situated. In an embodiment, the wellbore
parameter sensing system 600 may further comprise a plurality of
regional communication units 610, which may be situated on the
casing 20 and spaced at regular or irregular intervals along the
casing, e.g., about every 5 m to 15 m along the length of the
casing 20, alternatively about every 8 m to 12 m along the length
of the casing 20, alternatively about every 10 m along the length
of the casing 20. In embodiments, the regional communication units
610 may be situated on or in casing collars that couple casing
joints together. In addition, the regional communication units 610
may be situated in an interior of the casing 20, on an exterior of
the casing 20, or both. In an embodiment, the wellbore parameter
sensing system 600 may further comprise a tool (e.g., a data
interrogator 620 or other data collection and/or power-providing
device), which may be lowered down into the wellbore 18 on a
wireline 622, as well as a processor 630 or other data storage or
communication device, which is connected to the data interrogator
620.
[0113] In an embodiment, each regional communication unit 610 may
be configured to interrogate and/or receive data from, MEMS sensors
52 situated in the annulus 26, in the vicinity of the regional
communication unit 610, whereby the vicinity of the regional
communication unit 610 is defined as in the above discussion of the
wellbore parameter sensing system 300 illustrated in FIG. 5. The
MEMS sensors 52 may be configured to transmit MEMS sensor data to
neighboring MEMS sensors 52, as denoted by double arrows 632, as
well as to transmit MEMS sensor data to the regional communication
units 610 in their respective vicinities, as denoted by single
arrows 634. In an embodiment, the MEMS sensors 52 may be passive
sensors that are powered by bursts of electromagnetic radiation
from the regional communication units 610. In a further embodiment,
the MEMS sensors 52 may be active sensors that are powered by
batteries situated in or on the MEMS sensors 52 or by other
downhole power sources.
[0114] In contrast with the embodiment of the wellbore parameter
sensing system 300 illustrated in FIG. 5, the regional
communication units 610 in the present embodiment of the wellbore
parameter sensing system 600 are neither wired to one another, nor
wired to the processor 630 or other surface equipment. Accordingly,
in an embodiment, the regional communication units 610 may be
powered by batteries, which enable the regional communication units
610 to interrogate the MEMS sensors 52 in their respective
vicinities and/or receive MEMS sensor data from the MEMS sensors 52
in their respective vicinities. The batteries of the regional
communication units 610 may be inductively rechargeable by the data
interrogator 620 or may be rechargeable by other downhole power
sources. In addition, as set forth above, the data interrogator 620
may be lowered into the wellbore 18 for the purpose of
interrogating regional communication units 610 and receiving the
MEMS sensor data stored in the regional communication units 610.
Furthermore, the data interrogator 620 may be configured to
transmit the MEMS sensor data to the processor 630, which processes
the MEMS sensor data. In an embodiment, a fluid containing MEMS in
contained within the wellbore casing (for example, as shown in
FIGS. 5, 6, 7, and 10), and the data interrogator 620 is conveyed
through such fluid and into communicative proximity with the
regional communication units 610. In various embodiments, the data
interrogator 620 may communicate with, power up, and/or gather data
directly from the various MEMS sensors distributed within the
annulus 26 and/or the casing 20, and such direct interaction with
the MEMS sensors may be in addition to or in lieu of communication
with one or more of the regional communication units 610. For
example, if a given regional communication unit 610 experiences an
operational failure, the data interrogator 620 may directly
communicate with the MEMS within the given region experiencing the
failure, and thereby serve as a backup (or secondary/verification)
data collection option.
[0115] Referring to FIG. 9, a schematic view of an embodiment of a
wellbore parameter sensing system 700 is illustrated. As in
earlier-described embodiments, the wellbore parameter sensing
system 700 comprises the wellbore 18 and the casing 20 that is
situated inside the wellbore 18. In addition, as in the case of
other embodiments illustrated in the Figures (e.g., FIGS. 5 and 8),
the wellbore parameter sensing system 700 comprises a plurality of
regional communication units 710, which may be situated on the
casing 20 and spaced at regular or irregular intervals along the
casing, e.g., about every 5 m to 15 m along the length of the
casing 20, alternatively about every 8 m to 12 m along the length
of the casing 20, alternatively about every 10 m along the length
of the casing 20. In embodiments, the regional communication units
710 may be situated on or in casing collars that couple casing
joints together. In addition, the regional communication units 710
may be situated in an interior of the casing 20, on an exterior of
the casing 20, or both, or may be otherwise located and supported
as described in various embodiments herein.
[0116] In contrast to the embodiment of the wellbore parameter
sensing system 300 illustrated in FIG. 5, in an embodiment, the
wellbore parameter sensing system 700 further comprises one or more
primary (or master) communication units 720. The regional
communication units 710a and the primary communication unit 720a
may be coupled to one another by a data line 730, which allows
sensor data obtained by the regional communication units 710a from
MEMS sensors 52 situated in the annulus 26 to be transmitted from
the regional communication units 710a to the primary communication
unit 720a, as indicated by directional arrows 732.
[0117] In an embodiment, the MEMS sensors 52 may sense at least one
wellbore parameter and transmit data regarding the at least one
wellbore parameter to the regional communication units 710b, either
via neighboring MEMS sensors 52 as denoted by double arrow 734, or
directly to the regional communication units 710 as denoted by
single arrows 736. The regional communication units 710b may
communicate wirelessly with the primary or master communication
unit 720b, which may in turn communicate wirelessly with equipment
located at the surface (or via telemetry such as casing signal
telemetry) and/or other regional communication units 720a and/or
other primary or master communication units 720a.
[0118] In embodiments, the primary or master communication units
720 gather information from the MEMS sensors and transmit (e.g.,
wirelessly, via wire, via telemetry such as casing signal
telemetry, etc.) such information to equipment (e.g., processor
750) located at the surface.
[0119] In an embodiment, the wellbore parameter sensing system 700
further comprises, additionally or alternatively, a data
interrogator 740, which may be lowered into the wellbore 18 via a
wire line 742, as well as a processor 750, which is connected to
the data interrogator 740. In an embodiment, the data interrogator
740 is suspended adjacent to the primary communication unit 720,
interrogates the primary communication unit 720, receives MEMS
sensor data collected by all of the regional communication units
710 and transmits the MEMS sensor data to the processor 750 for
processing. The data interrogator 740 may provide other functions,
for example as described with reference to data interrogator 620 of
FIG. 8. In various embodiments, the data interrogator 740 (and
likewise the data interrogator 620) may communicate directly or
indirectly with any one or more of the MEMS sensors (e.g., sensors
52), local or regional data interrogation/communication untits
(e.g., units 310, 510, 610, 710), primary or master communication
units (e.g., units 720), or any combination thereof.
[0120] Referring to FIG. 10, a schematic view of an embodiment of a
wellbore parameter sensing system 800 is illustrated. As in
earlier-described embodiments, the wellbore parameter sensing
system 800 comprises the wellbore 18 and the casing 20 that is
situated inside the wellbore 18. In addition, as in the case of
other embodiments shown in FIGS. 5-9, the wellbore parameter
sensing system 800 comprises a plurality of local, regional, and/or
primary/master communication units 810, which may be situated on
the casing 20 and spaced at regular or irregular intervals along
the casing 20, e.g., about every 5 m to 15 m along the length of
the casing 20, alternatively about every 8 m to 12 m along the
length of the casing 20, alternatively about every 10 m along the
length of the casing 20. In embodiments, the communication units
810 may be situated on or in casing collars that couple casing
joints together. In addition, the communication units 810 may be
situated in an interior of the casing 20, on an exterior of the
casing 20, or both, or may be otherwise located and supported as
described in various embodiments herein.
[0121] In an embodiment, MEMS sensors 52, which are present in a
wellbore servicing fluid that has been placed in the wellbore 18,
may sense at least one wellbore parameter and transmit data
regarding the at least one wellbore parameter to the local,
regional, and/or primary/master communication units 810, either via
neighboring MEMS sensors 52 as denoted by double arrows 812, 814,
or directly to the communication units 810 as denoted by single
arrows 816, 818.
[0122] In an embodiment, the wellbore parameter sensing system 800
may further comprise a data interrogator 820, which is connected to
a processor 830 and is configured to interrogate each of the
communication units 810 for MEMS sensor data via a ground
penetrating signal 822 and to transmit the MEMS sensor data to the
processor 830 for processing.
[0123] In a further embodiment, one or more of the communication
units 810 may be coupled together by a data line (e.g., wired
communications). In this embodiment, the MEMS sensor data collected
from the MEMS sensors 52 by the regional communication units 810
may be transmitted via the data line to, for example, the regional
communication unit 810 situated furthest uphole. In this case, only
one regional communication unit 810 is interrogated by the surface
located data interrogator 820. In addition, since the regional
communication unit 810 receiving all of the MEMS sensor data is
situated uphole from the remainder of the regional communication
units 810, an energy and/or parameter (intensity, strength,
wavelength, amplitude, frequency, etc.) of the ground penetrating
signal 822 may be able to be reduced. In other embodiments, a data
interrogator such as unit 620 or 740) may be used in addition to or
in lieu of the surface unit 810, for example to serve as a back-up
in the event of operation difficulties associated with surface unit
820 and/or to provide or serve as a relay between surface unit 820
and one or more units downhole such as a regional unit 810 located
at an upper end of a string of interrogator units.
[0124] For sake of clarity, it should be understood that like
components as described in any of FIGS. 5-10 may be combined and/or
substituted to yield additional embodiments and the functionality
of such components in such additional embodiments will be apparent
based upon the description of FIGS. 5-10 and the various components
therein. For example, in various embodiments disclosed herein
(including but not limited to the embodiments of FIGS. 5-10), the
local, regional, and/or primary/master communication/data
interrogation units (e.g., units 310, 510, 610, 620, 710, 740,
and/or 810) may communicate with one another and/or equipment
located at the surface via signals passed using a common structural
support as the transmission medium (e.g., casing, tubular,
production tubing, drill string, etc.), for example by encoding a
signal using telemetry technology such as an electrical/mechanical
transducer. In various embodiments disclosed herein (including but
not limited to the embodiments of FIGS. 5-10), the local, regional,
and/or primary/master communication/data interrogation units (e.g.,
units 310, 510, 610, 620, 710, 740, and/or 810) may communicate
with one another and/or equipment located at the surface via
signals passed using a network formed by the MEMS sensors (e.g., a
daisy-chain network) distributed along the wellbore, for example in
the annular space 26 (e.g., in a cement) and/or in a wellbore
servicing fluid inside casing 20. In various embodiments disclosed
herein (including but not limited to the embodiments of FIGS.
5-10), the local, regional, and/or primary/master
communication/data interrogation units (e.g., units 310, 510, 610,
620, 710, 740, and/or 810) may communicate with one another and/or
equipment located at the surface via signals passed using a ground
penetrating signal produced at the surface, for example being
powered up by such a ground-penetrating signal and transmitting a
return signal back to the surface via a reflected signal and/or a
daisy-chain network of MEMS sensors and/or wired communications
and/or telemetry transmitted along a mechanical conveyance/medium.
In some embodiments, one or more of), the local, regional, and/or
primary/master communication/data interrogation units (e.g., units
310, 510, 610, 620, 710, 740, and/or 810) may serve as a relay or
broker of signals/messages containing information/data across a
network formed by the units and/or MEMS sensors.
[0125] Referring to FIG. 11, a method 900 of servicing a wellbore
is described. At block 910, a plurality of MEMS sensors is placed
in a wellbore servicing fluid. At block 920, the wellbore servicing
fluid is placed in a wellbore. At block 930, data is obtained from
the MEMS sensors, using a plurality of data interrogation units
spaced along a length of the wellbore. At block 940, the data
obtained from the MEMS sensors is processed.
[0126] Referring to FIG. 12, a further method 1000 of servicing a
wellbore is described. At block 1010, a plurality of MEMS sensors
is placed in a wellbore servicing fluid. At block 1020, the
wellbore servicing fluid is placed in a wellbore. At block 1030, a
network consisting of the MEMS sensors is formed. At block 1040,
data obtained by the MEMS sensors is transferred from an interior
of the wellbore to an exterior of the wellbore via the network
consisting of the MEMS sensors. Any of the embodiments set forth in
the Figures described herein, for example, without limitation,
FIGS. 5-10, may be used in carrying out the methods as set forth in
FIGS. 11 and 12.
[0127] In some embodiments, a conduit (e.g., casing 20 or other
tubular such as a production tubing, drill string, workstring, or
other mechanical conveyance, etc.) in the wellbore 18 may be used
as a data transmission medium, or at least as a housing for a data
transmission medium, for transmitting MEMS sensor data from the
MEMS sensors 52 and/or interrogation/communication units situated
in the wellbore 18 to an exterior of the wellbore (e.g., earth's
surface 16). Again, it is to be understood that in various
embodiments referencing the casing, other physical supports may be
used as a data transmission medium such as a workstring,
toolstring, production string, tubular, coiled tubing, wireline,
jointed pipe, or any other physical structure or conveyance
extending downhole from the surface.
[0128] Referring to FIG. 13, a schematic cross-sectional view of an
embodiment of the casing 1120 is illustrated. The casing 1120 may
comprise a groove, cavity, or hollow 1122, which runs
longitudinally along an outer surface 1124 of the casing, along at
least a portion of a length of the 1120 casing. The groove 1122 may
be open or may be enclosed, for example with an exterior cover
applied over the groove and attached to the casing (e.g., welded)
or may be enclosed as an integral portion of the casing
body/structure (e.g., a bore running the length of each casing
segment). In an embodiment, at least one cable 1130 may be embedded
or housed in the groove 1122 and run longitudinally along a length
of the groove 1122. The cable 1130 may be insulated (e.g.,
electrically insulated) from the casing 1120 by insulation 1132.
The cable 1130 may be a wire, fiber optic, or other physical medium
capable of transmitting signals.
[0129] In an embodiment, a plurality of cables 1130 may be situated
in groove 1122, for example, one or more insulated electrical lines
configured to power pieces of equipment situated in the wellbore 18
and/or one or more data lines configured to carry data signals
between downhole devices and an exterior of the wellbore 18. In
various embodiments, the cable 1130 may be any suitable electrical,
signal, and/or data communication line, and is not limited to
metallic conductors such as copper wires but also includes fiber
optical cables and the like.
[0130] FIG. 14 illustrates an embodiment of a wellbore parameter
sensing system 1100, comprising the wellbore 18 inside which a
wellbore servicing fluid loaded with MEMS sensors 52 is situated;
the casing 1120 having a groove 1122; a plurality of data
interrogation/communication units 1140 situated on the casing 1120
and spaced along a length of the casing 1120; a processing unit
1150 situated at an exterior of the wellbore 18; and a power supply
1160 situated at the exterior of the wellbore 18.
[0131] In embodiments, the data interrogation/communication units
1140 may be situated on or in casing collars that couple casing
joints together. In addition or alternatively, the data
interrogation/communication units 1140 may be situated in an
interior of the casing 1120, on an exterior of the casing 1120, or
both. In an embodiment, the data interrogation/communication units
1140a may be connected to the cable(s) and/or data line(s) 1130 via
through-holes 1134 in the insulation 1132 and/or the casing (e.g.,
outer surface 1124). The data interrogation/communication units
1140a may be connected to the power supply 1160 via cables 1130, as
well as to the processor 1150 via data line(s) 1133. The data
interrogation/communication units 1140a commonly connected to one
or more cables 1130 and/or data lines 1133 may function (e.g.,
collect and communication MEMS sensor data) in accordance with any
of the embodiments disclosed herein having wired
connections/communications, including but not limited to FIGS. 5,
7, and 9. Furthermore, the wellbore parameter sensing system 1100
may further comprise one or more data interrogation/communication
units 1140b in wireless communication and may function (e.g.,
collect and communication MEMS sensor data) in accordance with any
of the embodiments disclosed herein having wireless
connections/communications, including but not limited to FIGS. 5,
7, 8, 9, and 10.
[0132] By way of non-limiting example, the MEMS sensors 52 present
in a wellbore servicing fluid situated in an interior of the casing
1120 and/or in the annulus 26 measure at least one wellbore
parameter. The data interrogation/communication units 1140 in a
vicinity of the MEMS sensors 52 interrogate the sensors 52 at
regular intervals and receive data from the sensors 52 regarding
the at least one wellbore parameter. The data
interrogation/communication units 1140 then transmit the sensor
data to the processor 1150, which processes the sensor data.
[0133] In an embodiment, the MEMS sensors 52 may be passive
sensors, i.e., may be powered, for example, by bursts of
electromagnetic radiation from the regional data
interrogation/communication units 1140. In a further embodiment,
the MEMS sensors 52 may be active sensors, i.e., powered by a
battery or batteries situated in or on the sensors 52 or other
downhole power source. In an embodiment, batteries of the MEMS
sensors 52 may be inductively rechargeable by the regional data
interrogation/communication units 1140.
[0134] In a further embodiment, the casing 1120 may be used as a
conductor for powering the data interrogation/communication units
1140, or as a data line for transmitting MEMS sensor data from the
data interrogation/communication units 1140 to the processor
1150.
[0135] FIG. 15 illustrates an embodiment of a wellbore parameter
sensing system 1200, comprising the wellbore 18 inside which a
wellbore servicing fluid loaded with MEMS sensors 52 is situated;
the casing 20; a plurality of data interrogation/communication
units 1210 situated on the casing 20 and spaced along a length of
the casing 20; and a processing unit 1220 situated at an exterior
of the wellbore 18.
[0136] In embodiments, the data interrogation/communication units
1210 may be situated on or in casing collars that couple casing
joints together. In addition or alternatively, the data
interrogation/communication units 1210 may be situated in an
interior of the casing 20, on an exterior of the casing 20, or
both. In embodiments, the data interrogation/communication units
1210 may each comprise an acoustic transmitter, which is configured
to convert MEMS sensor data received by the data
interrogation/communication units 1210 from the MEMS sensors 52
into acoustic signals that take the form of acoustic vibrations in
the casing 20, which may be referred to as acoustic telemetry
embodiments. In embodiments, the acoustic transmitters may operate,
for example, on a piezoelectric or magnetostrictive principle and
may produce axial compression waves, torsional waves, radial
compression waves or transverse waves that propagate along the
casing 20 in an uphole direction denoted by arrows 1212. A
discussion of acoustic transmitters as part of an acoustic
telemetry system is given in U.S. Patent Application Publication
No. 2010/0039898 and U.S. Pat. Nos. 3,930,220; 4,156,229;
4,298,970; and 4,390,975, each of which is hereby incorporated by
reference in its entirety. In addition, the data
interrogation/communication units 1210 may be powered as described
herein in various embodiments, for example by internal batteries
that may be inductively rechargeable by a recharging unit run into
the wellbore 18 on a wireline or by other downhole power
sources.
[0137] In embodiments, the wellbore parameter sensing system 1200
further comprises at least one acoustic receiver 1230, which is
situated at or near an uphole end of the casing 20, receives
acoustic signals generated and transmitted by the acoustic
transmitters, converts the acoustic signals into electrical signals
and transmits the electrical signals to the processing unit 1220.
Arrows 1232 denote the reception of acoustic signals by acoustic
receiver 1230. In an embodiment, the acoustic receiver 1230 may be
powered by an electrical line running from the processing unit 1220
to the acoustic receiver 1230.
[0138] In embodiments, the wellbore parameter sensing system 1200
further comprises a repeater 1240 situated on the casing 20. The
repeater 1240 may be configured to receive acoustic signals from
the data interrogation/communication units 1210 situated downhole
from the repeater 1240, as indicated by arrows 1242. In addition,
the repeater 1240 may be configured to retransmit, to the acoustic
receiver 1230, acoustic signals regarding the data received by
these downhole data interrogation/communication units 1210 from
MEMS sensors 52. Arrows 1244 denote the retransmission of acoustic
signals by repeater 1240. In further embodiments, the wellbore
parameter sensing system 1200 may comprise multiple repeaters 1230
spaced along the casing 20. In various embodiments, the data
interrogation/communication units 1210 and/or the repeaters 1230
may contain suitable equipment to encode a data signal into the
casing 20 (e.g, electrical/mechanical transducing circuitry and
equipment).
[0139] In operation, in an embodiment, the MEMS sensors 52 situated
in the interior of the casing 20 and/or in the annulus 26 may
measure at least one wellbore parameter and then transmit data
regarding the at least one wellbore parameter to the data
interrogation/communication units 1210 in their respective
vicinities in accordance with the various embodiments disclosed
herein, including but not limited to FIGS. 5-12. The acoustic
transmitters in the data interrogation/communication units 1210 may
convert the MEMS sensor data into acoustic signals that propagate
up the casing 20. The repeater or repeaters 1240 may receive
acoustic signals from the data interrogation/communication units
1210 downhole from the respective repeater 1240 and retransmit
acoustic signals further up the casing 20. At or near an uphole end
of the casing 20, the acoustic receiver 1230 may receive the
acoustic signals propagated up the casing 20, convert the acoustic
signals into electrical signals and transmit the electrical signals
to the processing unit 1220. The processing unit 1220 then
processes the electrical signals. In various embodiments, the
acoustic telemetry embodiments and associated equipment may be
combined with a network formed by the MEMS sensors and/or data
interrogation/communication units (e.g., a point to point or
"daisy-chain" network comprising MEMS sensors) to provide back-up
or redundant wireless communication network functionality for
conveying MEMS data from downhole to the surface. Of course, such
wireless communications and networks could be further combines with
various wired embodiments disclosed herein for further operational
advantages.
[0140] Referring to FIG. 16, a method 1300 of servicing a wellbore
is described. At block 1310, a plurality of MEMS sensors is placed
in a wellbore servicing fluid. At block 1320, the wellbore
servicing fluid is placed in a wellbore. At block 1330, data is
obtained from the MEMS sensors, using a plurality of data
interrogation units spaced along a length of the wellbore. At block
1340, the data is telemetrically transmitted from an interior of
the wellbore to an exterior of the wellbore, using a casing
situated in the wellbore (e.g., via acoustic telemetry). At block
1350, the data obtained from the MEMS sensors is processed.
[0141] Referring to FIG. 17, a schematic longitudinal sectional
view of a portion of the wellbore 18 is illustrated. As is apparent
from the Figure, the wellbore 18 includes at least one washed-out
region 42 at which material has broken off or eroded from a wall of
the wellbore 18 (or the wellbore has intersected a naturally
occurring void space within the formation, e.g., a lost circulation
zone), as well as at least one constricted region 44, for example
caused by particular inflow from the formation into the wellbore, a
partial wellbore collapse, a ledge or build-up of filter cake, or
the like may be present. In an embodiment, a wellbore servicing
fluid containing MEMS sensors may be pumped down the annulus 26 at
a fluid flow rate and up the interior flow bore of casing 20 so as
to establish a circulation loop. However, in a further embodiment,
wellbore servicing fluid containing MEMS sensors may be pumped down
the interior flow bore of casing 20 and up the annulus 26.
[0142] In further regard to FIG. 17, a MEMS sensor loading of the
wellbore servicing fluid may be approximately constant throughout
the fluid. In an embodiment, as the wellbore servicing fluid is
pumped down the annulus 26 and up the casing 20, positions and
velocities of the MEMS sensors may be determined along the entire
length of the wellbore 18 using data interrogation/communication
units 150. In some embodiments, the various data
interrogation/communication units otherwise shown or described
herein may be used to detect the MEMS sensors, determine the
velocities thereof and otherwise communicate, store, and/or
transfer data (e.g., form various networks), and any suitable
configuration or layout of data interrogation/communication units
as described herein may be employed to determine velocities, flow
rates, concentrations, etc. of MEMS sensors, including but not
limited to the embodiments of FIGS. 5-16. For example, any of the
data interrogator embodiments shown in FIGS. 5-16 may be used in
combination with the data interrogation units of FIGS. 17 and 19.
Given the fluid flow rate of the wellbore servicing fluid and an
expected clearance between the casing 20 and the wellbore 18 in,
for example, regions 46, 48, 50 in which the wellbore 18 is not
enlarged or constricted, an approximate expected fluid velocity
through these regions 46, 48 and 50 may be calculated. Furthermore,
since the MEMS sensors are distributed throughout the wellbore
servicing fluid and are carried along with the wellbore servicing
fluid as the wellbore servicing fluid moves down the annulus 26,
the velocities of the MEMS sensors in a downhole direction will at
least approximately correspond to the calculated fluid velocity for
regions 46, 48 and 50 of the wellbore 18. Accordingly, if, in a
region of the wellbore 18, the downhole velocities of the MEMS
sensors are approximately equal to the expected fluid velocity or
deviate from the expected fluid velocity by less than a threshold
value, it may be concluded that a cross-sectional area of the
annulus 26 in this region approximately corresponds to an expected
cross-sectional area of the wellbore 18 minus an expected
cross-sectional area of the casing 20. Likewise, if the fluid
velocity deviates equal to or greater than a threshold value (e.g.,
higher or lower velocity than expected), such deviation may
indicate the present of an undesirable constriction or expansion
(e.g., volumetric constriction or expansion) of the wellbore.
[0143] In an embodiment, if the wellbore servicing fluid moves
through a washed out region of the wellbore 18 such as moving from
region 46 to region 42, the fluid velocity of the wellbore
servicing fluid will decrease as the wellbore servicing fluid
traverses from region 46 to region 42, and then increase again as
the wellbore servicing fluid enters regions 48 of the wellbore 18.
Accordingly, as the MEMS sensors traverse region 42 of the wellbore
18, the average downhole velocity of the MEMS sensors will decrease
in comparison to the average downhole velocity of the MEMS sensors
in region 46. In addition, if it is assumed, at least initially,
that no or minimal wellbore servicing fluid is being lost to the
wellbore 18, and that the fluid flow rate at which the wellbore
servicing fluid is being pumped through the wellbore 18 remains
approximately constant, then the fluid flow rate through every
annular cross-section of the wellbore 18 is approximately constant.
Thus, referring to FIG. 18a, which is a schematic annular
cross-section of the wellbore 18 taken at A-A in region 46 (and is
also representative of regions 48 and 50), and FIG. 18b, which is a
schematic annular cross-section of the wellbore 18 taken at B-B in
section 42, the fluid flow rate through these cross-sections
remains approximately constant despite the larger annular
cross-section of section B-B. If the fluid flow rate, e.g., in
m.sup.3/s, is referred to as f, the annular cross-sectional area,
e.g., in m.sup.2, of section A-A is referred to as A.sub.A, and the
annular cross-sectional area, e.g., in m.sup.2, of section B-B is
referred to as A.sub.B, then the average fluid velocities, e.g., in
m/s, in sections A-A and B-B, respectively referred to as v.sub.A
and v.sub.B, may be calculated as follows:
v.sub.A=f/A.sub.A 1)
v.sub.B=f/A.sub.B. 2)
In addition, rearranging terms and noting that f is constant, one
obtains:
f=v.sub.AA.sub.A=v.sub.BA.sub.B. 3)
Thus, if cross-sectional area A.sub.B of section B-B in FIG. 18b
is, e.g., 2 times greater than cross-sectional area A.sub.A of
section A-A in FIG. 18a, then the average downhole fluid velocity
v.sub.B through section B-B will be one half (e.g., 50%) of the
average downhole fluid velocity v.sub.A through section A-A. Stated
alternatively, a 50% reduction in velocity (e.g.,
v.sub.B=1/2v.sub.A) indicates a 100% increase in cross-sectional
area (e.g., A.sub.B=2A.sub.A). Accordingly, the average downhole
velocities of MEMS sensors 52 passing through an annular
cross-section of the wellbore 18 may be used to determine the
cross-sectional area of that annular cross-section, with a decrease
in fluid velocity representing an expansion in the wellbore such as
a washout, void space, vugular zone, fracture or other
space/opening in the wellbore.
[0144] Referring now to FIG. 18c, which illustrates a schematic
annular cross-section of the wellbore 18 taken at section C-C of
region 44 of the wellbore 18, it is apparent that at least a
portion of the annulus 26 at section C-C is constricted, for
example possibly due to a protruding ledge in the wellbore 18 or a
build-up of filter cake or other particulate matter in the wellbore
18. In an embodiment, if the wellbore servicing fluid moves through
a constricted region of the wellbore 18 such as region 44, the
average fluid velocity of the wellbore servicing fluid will
increase as the wellbore servicing fluid traverses from region 48
into region 44, and then decrease again as the wellbore servicing
fluid enters region 50 of the wellbore 18. Accordingly, as the MEMS
sensors 52 traverse region 44 of the wellbore 18, the average
downhole velocity of the MEMS sensors 52 will increase in
comparison to the average downhole velocity of the MEMS sensors 52
in region 48. Now, referring back to equation 3) and applying the
equation to cross-section C-C in region 44 of the wellbore 18, one
obtains:
f=v.sub.AA.sub.A=v.sub.CA.sub.C, 4)
where v.sub.C is an average downhole fluid velocity through
cross-section C-C and A.sub.C is a cross-sectional area of
cross-section C-C. Thus, if, for example, the average downhole
velocity of the MEMS sensors 52 passing through cross-section C-C
in region 44 is 2 times greater than the average downhole velocity
of the MEMS sensors 52 passing through cross-section A-A in region
46 (which would be comparable to an annular cross-section taken in
region 48), then the cross-sectional area A.sub.C of cross-section
C-C is one half (e.g., 50%) of the cross-sectional area of
cross-section A-A (or an equivalent cross-section taken in region
48). Accordingly, the average downhole velocities of the MEMS
sensors 52 passing through a constricted region of a wellbore 18
may be utilized to determine the cross-sectional area of an annular
cross-section taken in that constricted region, with an increase in
fluid velocity representing an constriction in the wellbore such as
a partial collapse, swelling, particulate buildup or inflow, filter
cake buildup, and the like.
[0145] FIG. 19 illustrates a schematic longitudinal sectional view
of a portion of the wellbore 18, in which a wellbore servicing
fluid containing MEMS sensors 52 is pumped down the annulus 26 at a
fluid flow rate and up the casing 20 so as to form a circulation
loop, with the understanding that fluid may flow in the opposite
direction in some embodiments. In addition, as is apparent from the
Figure, the wellbore 18 includes two fluid loss zones 54, 56 at
which respective fissures 58, 60 extend outwards from the wellbore
18 and communicate with a hollow or permeable formation 62.
Cross-sections of the wellbore 18 taken at lines E-E and G-G in
regions 54 and 56 of the wellbore 18 are schematically illustrated
in FIGS. 20b and 20d, respectively.
[0146] In an embodiment, as the wellbore servicing fluid passes
from region 62 through region 54, a portion of the fluid is pressed
(e.g., lost) through the fissure 58 and absorbed by formation 62.
Such areas where a wellbore composition is lost to the surrounding
formation may be referred to as fluid loss zone, loss or lost
circulation zones, wash-outs, voids, vugulars, cavities, fissures,
fractures, etc. If the fluid flow rate is referred to as f and the
flow rate of fluid lost to the formation 62 via fissure 58 is
referred to as f.sub.u, then the flow rate of fluid passing through
annular cross-section D-D, which is situated in a region 62 of the
wellbore 18 directly uphole from fissure 58 and is schematically
illustrated in FIG. 20a, is f, whereas the flow rate of fluid
passing through annular cross-section F-F, which is situated in a
region 64 of the wellbore 18 directly downhole from fissure 58 and
is schematically illustrated in FIG. 20c, is f-f.sub.L1. Similarly,
as the wellbore servicing fluid passes from region 64 through
region 56, a portion of the fluid is pressed (e.g., lost) through
the fissure 60 and absorbed by formation 62. If the flow rate of
fluid lost to the formation 62 via fissure 60 is referred to as
f.sub.L2, then the flow rate of fluid passing through annular
cross-section H-H, which is situated in a region 66 of the wellbore
18 directly downhole from fissure 60 and is schematically
illustrated in FIG. 20e, is f-(f.sub.L1+f.sub.L2). Now, considering
the relationship between the fluid flow rate and the flow velocity
given in equation 3), one obtains:
f=v.sub.DA.sub.D 5)
f-f.sub.L1=v.sub.FA.sub.F 6)
f-(f.sub.L1+f.sub.L2)=v.sub.HA.sub.H 7)
where v.sub.D, is the downhole flow velocity of the wellbore
servicing fluid through annular cross-section D-D, A.sub.D is the
cross-sectional area of annular cross-section D-D, v.sub.F is the
downhole flow velocity of the wellbore servicing fluid through
annular cross-section F-F, A.sub.F is the cross-sectional area of
annular cross-section F-F, v.sub.H is the downhole flow velocity of
the wellbore servicing fluid through annular cross-section H-H, and
A.sub.H is the cross-sectional area of annular cross-section H-H.
Assuming that none of regions 62, 64 and 66 includes a washed-out
section or a constriction, then A.sub.D, A.sub.F and A.sub.H may be
considered to be approximately equal to one another and referred to
as A:
A=A.sub.D=A.sub.F=A.sub.H 8)
After combining equation 8) with equations 5), 6) and 7) and
rearranging terms, one obtains:
v D = 1 A ( f ) 9 ) v F = 1 A ( f - f L 1 ) 10 ) v H = 1 A ( f - f
L 1 - f L 2 ) 11 ) ##EQU00001##
Thus, after a fluid loss zone is traversed by the wellbore
servicing fluid, the downhole flow velocity of the wellbore
servicing fluid, and thus the average downhole velocity of the MEMS
sensors 52 situated in the wellbore servicing fluid, will decrease
in proportion with the fluid flow rate. Accordingly, in an
embodiment, if a decrease in the average downhole MEMS sensor
velocity is detected, then an approximate flow rate of wellbore
servicing fluid lost to a formation may be calculated from the
decrease in the average downhole MEMS sensor velocity.
[0147] It should be noted from the discussion above that an average
downhole velocity of MEMS sensors 52 will decrease in both a
washed-out region and a fluid loss zone. However, in an embodiment,
a washed-out region and a fluid loss zone may be distinguished from
one another in that in the case of a washed-out region, after the
washed-out region is traversed, the average downhole velocity of
the MEMS sensors will return to approximately the average MEMS
sensor downhole velocity detected uphole from the washed-out region
given that the total flow rate remains constant (i.e., there is no
significant loss of fluid to the surrounding formation). In
contrast, after the wellbore servicing fluid traverses a fluid loss
zone, the average downhole velocity of the MEMS sensors 52 will not
return to an average downhole MEMS sensor velocity detected uphole
from the fluid loss zone, but will remain at a lower level.
[0148] In further regard to FIG. 19, in an embodiment, a return
fluid flow rate 68 up the casing 20 to, for example, circulating
pumps situated at the rig 12, may be determined from a flow meter
situated upstream from the circulating pumps and compared to the
original fluid flow rate of wellbore servicing fluid, and the flow
rate of wellbore servicing fluid lost to the formation 62 may be
calculated and compared to the fluid loss indicated by the
decreases in the average downhole MEMS sensor velocities. Upon
detecting and/or locating fluid loss to the surrounding formation,
remedial actions may be taken such as pumping a lost circulation
material downhole to plug the leak, performing a squeeze job (e.g.,
cement squeeze, gunk squeeze), etc.
[0149] In an alternative embodiment, all or a portion of the MEMS
sensors are given unique identifiers, for example RFID serial
numbers, and the data interrogation units 150 may be used to keep
track of all or a portion of the uniquely identified sensors (e.g.,
a statistic sampling of same). For example, where unit 150d records
the presence of 100 uniquely identified MEMS sensors within a given
sampling period, a failure by one or more downstream units (e.g.,
unit 150h) to detect a representative or threshold number of the
same 100 uniquely identified MEMS sensors within an expected
sampling time (e.g., the time expected for the sensors to travel
the distance between units 150d and 150h based upon the fluid flow
rate) may indicate a loss of said sensors to the surrounding
formation, for example via fissures 58 and/or 60, taking into
account any normal variance in detection of uniquely identified
MEMS sensors between upstream and downstream interrogation units
over a given distance. For example, if over a statistically
representative sampling period, only 80 of the 100 uniquely
identified MEMS sensors for each sampling period are detected at a
downstream interrogation unit, such may indicate a 20% fluid loss
to the formation (or a fluid loss of 20% minus the normal
variance/deviation in MEMS detection).
[0150] In addition to or in lieu of (a) estimating a
cross-sectional area of an annular cross-section of a wellbore,
using a fluid flow rate of a MEMS sensor-loaded wellbore servicing
fluid through the wellbore and the velocities of the MEMS sensors
during traversal of the annular cross-section, and/or (b)
estimating a flow rate of fluid lost to a formation in an annular
region of a wellbore, using velocities of the MEMS sensors 52
uphole and downhole from the annular region, in various
embodiments, (c) shapes of annular cross-sections of the wellbore
18 may be estimated, using detected positions of the MEMS sensors
52, and any combination of (a), (b), and (c) is contemplated
hereby, which may be referred to in some instances as annular
mapping via flow rate and/or velocities of MEMS sensors conveyed
through a wellbore (e.g., circulated through an annulus) via a
wellbore servicing composition. In performing any annular mapping
function, e.g., any of (a), (b), and/or (c) of this paragraph, the
data interrogation units 150 may be spaced along the wellbore and
supported upon the casing or other conveyance or structure in the
wellbore. While fixed data interrogators are shown in FIGS. 17 and
19, one or more mobile data interrogators (for example, as shown in
FIGS. 2 and 8), may be employed to perform annular mapping
functions, for example tripped into the wellbore and intermittently
moved up the wellbore while mapping same. The data interrogation
units 150 have a sensing or mapping range associated therewith, as
represented by circles 151. Within the sensing or mapping range,
the data interrogation units 150 are operable to sense the presence
of various MEMS sensors in relation to the unit, and thus can
create a mathematical representation of MEMS sensor presence,
velocity, location, concentration, and/or identity (e.g., a
particular sensor or group of sensors having a unique identifier or
I.D. number) in relation to the position of a given unit 150. By
way of analogy and shown schematically in FIGS. 17 and 19, the data
interrogation units 150 constitute an overlapping network of "radar
ranges" and thus can track the presence, location, concentration,
velocity, and/or identity of the MEMS sensors as they flow through
the wellbore with the servicing composition.
[0151] Referring back to FIGS. 17 and 18a to 18c, FIGS. 18a to 18c
schematically and respectively depict annular cross-sections of the
wellbore 18 at lines A-A, B-B and C-C in FIG. 17. As is apparent
from FIGS. 18a to 18c, MEMS sensors 52 suspended in the wellbore
servicing fluid traverse these cross-sections. In an embodiment,
positions of the MEMS sensors 52 in the annular cross-sections,
e.g., radial positions (or directional vector) of the MEMS sensors
52 with respect to the data interrogation units 150, may be
determined and mapped. In addition, a curve may be drawn through
the innermost MEMS sensor positions with respect to the casing 20,
as well as through the outermost MEMS sensor positions, in order to
approximate an outline of a wall of the wellbore 18 and an outer
wall of the casing 20 in each cross-section, and such may be
carried out in three dimensions (e.g., x, y, and z coordinates with
respect to the data interrogation units 150) to provide a map of
the annular geometry and/or surrounding formation. In an
embodiment, positions of MEMS sensors 52 in an annular
cross-section may be recorded and mapped over a time frame ranging
from about 0.5 s to about 10 s, and over a distance (e.g., a
distance from any given data interrogation unit location) of 1 ft,
5 ft, 10 ft, or 25 ft, depending on the sensing range (e.g., power)
of the data interrogation units and/or the desired accuracy of an
annular cross-sectional depiction. Also, annular cross-sections may
be taken a longitudinal distances traversing the wellbore of from
about 0.25 ft, 0.5 ft, 0.75 ft, 1 ft, 1.5 ft, 2 ft, or any
combination thereof. In an embodiment, annular cross-sections may
be taken at longitudinal distances and/or intervals traversing the
wellbore about equivalent to the distances and/or intervals used in
wellbore logging activities, as would be apparent to those of skill
in the art. In other embodiments, annular cross-sections may be
taken a longitudinal distances and/or intervals traversing the
wellbore in accordance with other embodiments disclosed herein
(e.g., distances associated with processor 1720).
[0152] Referring back to FIG. 19, this Figure schematically depicts
regions 54 and 56 of the wellbore 18, at which wellbore servicing
fluid loaded with MEMS sensors 52 and pumped into the annulus 26 is
partially lost to a formation 62 via respective fissures 58, 60. In
addition, FIGS. 20b and 20d schematically depict cross-sections of
the wellbore 18 taken at wellbore-side ends of the fissures 58, 60
at lines E-E and G-G in FIG. 19. In an embodiment, as shown in
FIGS. 20b and 20d, cross-sections of the annulus 26 at the fissures
58, 60 may be mapped by recording positions of MEMS sensors 52 that
pass through the annulus 26 and the fissures 58, 60. In addition,
in a further embodiment, multiple annular cross-sections along the
length of the wellbore 18 and in the vicinity of the fissures 58,
60 may be mapped and combined, in order to form a three dimensional
depiction of at least a portion of the fissures 58, 60 and/or the
formation 62 and to possibly facilitate the filling and sealing of
the fissures 58, 60, e.g., a cement squeeze or plugging a lost
circulation zone.
[0153] As a result of determining the positions of the MEMS sensors
52, in an embodiment, it may be determined, for example, that
annular cross-section A-A in FIG. 18a is normal, i.e., the casing
20 is properly centralized in the wellbore 18, and the wall of the
wellbore 18 is not enlarged and does not have any debris attached
to it; that the wellbore 18 at annular cross-section B-B in FIG.
18b is undesirably expanded, e.g., at least partially washed out
and/or contains a fluid loss zone (e.g., loss of circulation zone),
and thus may require remedial action such as secondary cementing to
shore up the wall; and/or that the wellbore 18 at annular
cross-section C-C in FIG. 18c is undesirably constricted, e.g.,
includes a ledge and/or attached debris and/or a build-up of filter
cake along at least a portion of the wellbore wall and may require
more fluid circulation or other remedial action to reduce/remove
the build-up, and/or that the casing 20 is not properly centralized
in the wellbore 18.
[0154] Referring to FIG. 21, a method 1360 of servicing a wellbore
is described. At block 1362, a plurality of
Micro-Electro-Mechanical System (MEMS) sensors is placed in a
wellbore servicing fluid. At block 1364, the wellbore servicing
fluid is pumped down the wellbore at a fluid flow rate. At block
1366, positions of the MEMS sensors in the wellbore are determined.
At block 1368, velocities of the MEMS sensors along a length of the
wellbore are determined. At block 1370, an approximate
cross-sectional area profile of the wellbore along the length of
the wellbore is determined from at least the velocities and/or
positions of the MEMS sensors and the fluid flow rate.
[0155] In addition to or in lieu of using MEMS sensor to determine
a characteristic or shape of the wellbore and/or surrounding
formation, the MEMS sensors may provide information regarding the
flow fluid (e.g., flow dynamics and characteristics) in the
wellbore and/or surrounding formation. A plurality of MEMS sensors
may be placed in a wellbore composition, the wellbore composition
flowed (e.g., pumped) into the wellbore and/or surrounding
formation (e.g., circulated in the wellbore), and one or more fluid
flow properties, characteristics, and/or dynamics of the wellbore
composition may be determined by data obtained from the MEMS
sensors moving/flowing in the wellbore and/or formation. The data
may be obtained from the MEMS sensors according to any of the
embodiments disclosed herein (e.g., one or more mobile data
interrogators tripped into and out of the wellbore and/or fixed
data interrogators positioned within the wellbore), and may be
further communicated/transmitted to/from or within the wellbore via
any of the embodiments disclosed herein.) For example, areas of
laminar and/or turbulent flow the wellbore composition may be
determined within the wellbore and/or surrounding formation, and
such information may be used to further characterize the wellbore
and/or surrounding formation. The velocity and flow rate of the
wellbore composition may further be obtained as described herein.
In an embodiment, data from the MEMS sensors is used to perform one
or more fluid flow dynamics calculations for the flow of the
wellbore composition through the wellbore and/or the surrounding
formation. For example, data from the MEMS sensors may be used as
input to a computational fluid dynamics equation or software. Such
information may be used in designing down hole tools, for example
designing a down hole tool/device in a manner to reduce drag and/or
turbulence associated with the tool/device as the wellbore
composition flows through and/or past the tool.
[0156] In an embodiment, fluid flow data for the wellbore
composition is obtained over at least a portion of the length of
the wellbore, thereby providing a fluid flow profile over said
length of wellbore. The fluid flow profile may be compared to a
theoretical or design standard fluid flow profile, for example in
real time during performance of a serving operation wherein the
wellbore composition is being placed in the wellbore. Such
comparison may be used to determine whether the service is
proceeding according to plan and/or to verify one or more
characteristics of the wellbore. For example, an area of turbulent
flow indicated by the MEMS sensors may correspond to a location of
a particular wellbore feature expected to provide turbulence, such
as the presence of a tool or device (e.g., casing collar,
centralizer, spacer, shoe, etc.) in the wellbore that the fluid is
flowing around or through which may be indicated or mapped in the
theoretical or design fluid flow profile. Likewise, turbulent or
non-turbulent (e.g., laminar) flow may indicate desirable or
undesirable characteristics of the fluid itself (e.g., desirable or
undesirable mixing, stratification, etc.) and/or the surrounding
surface that contacts the fluid (e.g., rough vs. smooth surfaces,
etc.).
[0157] By performing such comparisons in real time, the wellbore
service may be altered or adjusted as needed to improve the outcome
of the service. For example, one or more conditions of the wellbore
and/or surrounding formation may be altered based upon a MEMS
sensor derived indication of the fluid flow characteristics or
dynamics. In an embodiment, a build up of a material on an interior
surface of the wellbore and/or formation (e.g., gelled mud, filter
cake, screen out material, sand, etc.) is reduced or removed via a
remedial action such as acidizing, washing, physical
scraping/contact, changing a flow rate of the wellbore composition,
changing a characteristic of the wellbore composition, placing an
additional composition in the wellbore to react with the build up
or change a characteristic of the buildup, moving a conduit within
the wellbore, placing a tool downhole to physically contact and
removing the build up, or any combination thereof. In another
embodiment, a fluid flow property or characteristic is an actual
time of arrival of at least a portion of the wellbore composition
comprising the MEMS sensors. The actual time of arrival may be
compared to an expected time of arrival, and such comparison may be
indicative of a further condition of the wellbore. For example, an
expected time of arrival matching an actual time of arrival may be
indicative of normal or expected operations. Alternatively, an
actual time of arrival before an expected time of arrival may be
indicative of a decreased flow path through the wellbore (e.g.,
reduced flow bore diameter due to build up such as gelled mud,
filter cake or other flow restriction), thus yielding an increased
fluid velocity and decreased transit time for the MEMS sensors
flowing through the wellbore.
[0158] In an embodiment, the wellbore servicing operation comprises
placing a plurality of MEMS sensors in at least a portion of a
spacer fluid, a sealant composition (e.g., a cement slurry or a
non-cementitious sealant), or both, pumping the spacer fluid
followed by the sealant composition into the wellbore, and
determining one or more fluid flow properties or characteristics of
the spacer fluid and/or the cement composition from data provided
by the MEMS sensors during the pumping of the spacer fluid and
sealant composition into the wellbore. The sealant composition may
be pumped down the casing and back up the annular space between the
casing and the wellbore (e.g., a conventional cementing job) or may
be pumped down the annulus between the casing and the wellbore in a
reverse cementing job. The movement of the spacer and/or sealant
composition through the wellbore may be monitored via the MEMS
sensors, and such movement may be used to determine a
characteristic of the wellbore and/or surrounding formation; to
evaluate the fluid flow characteristics of the spacer fluid and/or
sealant composition as it flows through the wellbore and/or
surrounding formation; to determine a location of the spacer fluid
and/or sealant composition (e.g., when the sealant has turned the
corner at the terminal downhole end of the casing) and to further
signal or bring about a halt to the placement (e.g., stop pumping)
upon the spacer fluid and/or cement composition reaching a desired
location; and to monitor the wellbore for movement of the MEMS
sensors within the spacer fluid and/or sealant composition after
halting pumping of same and to signal an operator and/or activating
at least one device to prevent flow out of the wellbore upon
detection of movement of the MEMS sensors after halting the
pumping; or any combination thereof.
[0159] FIGS. 22a to 22c illustrate a schematic view of an
embodiment of a wellbore parameter sensing system 1400, which
comprises the wellbore 18, the casing 20 situated in the wellbore
18, a plurality of data interrogation units 1410 spaced along a
length of the casing 20, and a float shoe 1420 situated at a
downhole end of the casing 20. In an embodiment, the float shoe
1420 comprises a poppet valve 1422, which is biased by a spring
1424 when the valve 1422 is in a neutral state and may be opened if
a sufficient differential pressure develops between an interior of
the casing 20 and the annulus 26. While a float shoe and poppet
value assembly is demonstrated in this embodiment, it is understood
that any assembly (e.g., float collar, float shoe, valve assembly,
etc.) suitable to terminate the downhole, distal end of the casing
string (e.g., to protect and/or direct same into the wellbore) and
to selectively open and/or close terminal end of the casing to
fluid flow (from either interior to annulus or from annulus to
interior) may be employed in the various embodiments disclosed
herein, wherein communication with MEMS sensors may be used in
determining when to selectively perform said open and/or close and
wherein such communication may be with a data interrogation unit
located in and/or proximate such distal assembly (e.g., coupled to
and/or integral with a float collar, float shoe, valve assembly
etc.) and/or located in a moveable member flowing through the
wellbore (e.g., a wiper plug, ball, dart, etc.). Thus, detection
and/or communication with MEMS sensors by such data interrogation
units may signal the opening and/or closing of a valve proximate
the distal end of the casing in a conventional or reverse cementing
operation, thereby allowing for the selective placement of the
cement slurry.
[0160] In an embodiment, a cement slurry 1430 may be pumped down
the interior of the casing 20 in the direction of arrow 1432,
through the float shoe 1420 in the direction of arrows 1434, and up
the annulus 26 in the direction of arrows 1436 for the purpose of
cementing the casing 20 to a wall of the wellbore 18. The cement
slurry 1430 may include a slug 1440 of MEMS sensors 52 that may be
situated in a portion of the cement slurry 1430 that is pumped into
the wellbore 18 prior to a remainder of the cement slurry 1430,
e.g., positioned at a leading edge/portion, face, or head of the
slurry. In an embodiment, the MEMS sensors 52 are configured to
measure and/or convey at least one parameter of the wellbore 18,
e.g., a longitudinal position of the MEMS sensors 52 in the
wellbore 18, and transmit data regarding the longitudinal positions
of the MEMS sensors 52 in the wellbore 18 to the data interrogation
unit 1410 most proximate to the MEMS sensors 52. The data
interrogation units 1410 may then transmit the MEMS sensor data to
a processing unit situated at an exterior of the wellbore 18, and
such transmission may be carried out according to any embodiment
disclosed herein (e.g., the embodiments of FIGS. 5-16.
[0161] In an embodiment, as the cement slurry 1430 travels through
the wellbore 18, a longitudinal position of the slug 1440 of MEMS
sensors 52, and hence a longitudinal position of a head of the
cement slurry 1430, may be determined in real time via interaction
(e.g., communication) of the MEMS sensors 52 with the plurality of
data interrogation units 1410 spaced along a length of the casing.
For example, where all or a portion of the data interrogation units
1410 correspond with known locations in the wellbore (e.g., casing
collars located at a known depth in the wellbore), detection of
MEMS sensors by a given data interrogation unit 1410 indicates that
the slug of MEMS sensors (and thus the leading edge of the cement
slurry) is within the sensing/communication range of that
particular data interrogation unit 1410. As the slug of MEMS
sensors flows downward in the interior of the casing, the MEMS
sensors will be detected in an uphole to downhole sequence by the
data interrogation units 1410. In a further embodiment, a data
interrogation unit may be incorporated in the float shoe 1420 (or
located in close proximity thereto), thereby enabling a
determination of when the leading edge of the cement slurry 1430
reaches the end of the casing, "turns the corner," and enters the
annulus 26. Upon entering the annulus, the slug of MEMS sensors
will flow upward and will be detected in a downhole to uphole
sequence by the data interrogation units 1410. In a further
embodiment, pumping of the cement slurry 1430 may be controlled
(e.g., slowed and/or terminated) when the slug 1440 of MEMS sensors
52 is detected by a data interrogation unit 1410 situated most
proximate to the exterior of the wellbore 18, as illustrated in
FIG. 22c. Additionally or alternatively, a second slug of MEMS
sensors may be included at the trailing edge of the cement slurry,
thereby enabling a determination of when the trailing edge of the
cement slurry 1430 reaches the end of the casing, "turns the
corner," and enters the annulus 26. Based upon detection of the
first slug by a data interrogation unit (e.g., unit 1440) located a
known distance above the float shoe 1420 and/or detection of the
second slug by a data interrogation unit integral with and/or
proximate to the float shoe 1420, pumping of the cement slurry may
be controlled (e.g., slowed and/or stopped) to provide for precise
placement of the cement slurry into the annular space while, based
upon the design parameters of the well, likewise optionally
allowing for a controlled amount of cement to remain in the casing
proximate the float collar or optionally allowing for removal of
substantially all of the cement from the interior of the casing. In
an embodiment, detection of MEMS allows for controlled placement of
the cement slurry such that any contaminated cement (e.g., cement
contaminated with mud located in front of a cementing/wiper plug)
remains in the casing and/or shoe track and is not allowed to turn
the corner, exit the casing and reach the annulus, thereby ensuring
that all cement placed in the annulus is not contaminated and/or
compromised. Thus, MEMS may be used to avoid undesirably pushing a
contaminated wellbore servicing fluid into the annulus. In
addition, as also illustrated in FIG. 22c, when pumping of cement
slurry 1430 is terminated, the pressure differential between the
interior of the casing 20 and the annulus 26 decreases, thereby
causing the valve 1422 to close. As a result, the cement slurry
1430 is prevented from re-entering the casing 20.
[0162] Additionally or alternatively, the cement slurry (or other
wellbore fluid) may be monitored for movement of the MEMS sensors
after pumping has been terminated, as such movement may indicate a
problem with the closure of the terminal end of the casing (e.g.,
closing of a valve such as the float shoe valve) and/or otherwise
indicate a potential undesirable inflow and/or outflow into the
wellbore and resultant loss of zonal isolation. Such monitoring may
be performed in any cementing job (or other wellbore servicing
job), including but not limited to primary cementing (either
traditional cementing with flow down the casing and up the annulus
or reverse cementing with flow down the annulus) and/or secondary
cementing (e.g., remedial cementing, squeeze jobs, etc.). For
example, if a data interrogation unit located proximate the
terminal end of the casing being cemented (either convention or
reverse cementing) detects movement of MEMS sensors, such movement
may be associated with fluid flow into or out of the casing, which
may indicate that a valve associated with the terminal end of the
casing has not properly closed, i.e., the valve did not close
properly at the conclusion of cement pumping. Additionally or
alternatively, such movement may indicate an undesirable or
problematic movement of a wellbore fluid (e.g., cement slurry,
drilling fluid, isolation fluid, displacement fluid, production
fluids, etc.), for example due to loss into the formation and/or
flow of the fluid back up the wellbore (for example in response to
downhole pressure build-up, and thus indicating the potential for a
loss of zonal isolation or potentially a blowout). In an
embodiment, where undesirable movement of the wellbore fluid is
detected via movement of MEMS sensors, a signal may be generated to
trigger an alarm and/or activate one or more safety devices such as
downhole safety valves, blowout preventers, etc. In summary, if
MEMS sensors are detected as moving uphole when they shouldn't be,
then automatically and/or manually trigger one or more safety
devices to shut in the well. Detection of MEMS sensor movement may
be used in combination with other MEMS sensed parameters (e.g.,
detection of gas entering the wellbore) to provide further
cross-checking and/or redundancy to trigger alarms and/or safety
systems.
[0163] FIGS. 23a to 23c illustrate a schematic view of an
embodiment of a wellbore parameter sensing system 1500, which
comprises the wellbore 18, the casing 20 situated in the wellbore
18, a plurality of data interrogation units 1510 spaced along a
length of the casing 20, and a casing shoe 1520 situated at a
downhole end of the casing 20. In an embodiment, the casing shoe
1520 comprises a poppet valve 1522, which is biased open by a
spring 1524 when the valve 1522 is in a neutral state and may be
closed as the casing 20 is lowered into the wellbore 18. While a
float shoe and poppet value assembly is demonstrated in this
embodiment, it is understood that any assembly (e.g., float collar,
float shoe, valve assembly, etc.) suitable to terminate the
downhole, distal end of the casing string (e.g., to protect and/or
direct same into the wellbore) and to selectively open and/or close
terminal end of the casing to fluid flow (from either interior to
annulus or from annulus to interior) may be employed in the various
embodiments disclosed herein, wherein communication with MEMS
sensors may be used in determining when to selectively perform said
open and/or close and wherein such communication may be with a data
interrogation unit located in and/or proximate such distal assembly
(e.g., coupled to and/or integral with a float collar, float shoe,
valve assembly etc.) and/or located in a moveable member flowing
through the wellbore (e.g., a wiper plug, ball, dart, etc.). Thus,
detection and/or communication with MEMS sensors by such data
interrogation units may signal the opening and/or closing of a
valve proximate the distal end of the casing in a conventional or
reverse cementing operation, thereby allowing for the selective
placement of the cement slurry.
[0164] In an embodiment, a cement slurry 1530 may be pumped down
the annulus 26 in the direction of arrows 1532 for the purpose of
cementing the casing 20 to a wall of the wellbore 18. FIG. 23a
illustrates the wellbore 18 at the beginning of the pumping of the
cement slurry 1530, FIG. 23b illustrates the wellbore 18 when the
cement slurry 1530 is partway down the wellbore 18, and FIG. 23c
illustrates the wellbore 18 when the cement slurry 1530 has arrived
at or near a downhole end of the wellbore 18.
[0165] In an embodiment, the cement slurry 1530 may include a slug
1540 of MEMS sensors 52 that may be situated in a portion of the
cement slurry 1530 that is pumped into the wellbore 18 prior to a
remainder of the cement slurry 1530, e.g., positioned at a leading
edge/portion, face, or head of the slurry. In an embodiment, the
MEMS sensors 52 are configured to measure and/or convey at least
one parameter of the wellbore 18, e.g., a longitudinal position of
the MEMS sensors 52 in the wellbore 18, and transmit data regarding
the longitudinal positions of the MEMS sensors 52 in the wellbore
18 to the data interrogation unit 1510 most proximate to the MEMS
sensors 52. The data interrogation units 1510 may then transmit the
MEMS sensor data to a processing unit situated at an exterior of
the wellbore 18, and such transmission may be carried out according
to any embodiment disclosed herein (e.g., the embodiments of FIGS.
5-16).
[0166] In an embodiment, as the cement slurry 1530 travels down the
annulus 26, a longitudinal position of the slug 1540 of MEMS
sensors 52, and hence a longitudinal position of a head of the
cement slurry 1530, may be determined in real time via interaction
of the MEMS sensors 52 with the plurality of the data interrogation
units 1510 spaced along the length of the casing as described
herein (e.g., as described with reference to FIGS. 22a-c). In a
further embodiment, a data interrogation unit may be incorporated
in the casing shoe 1520 (or located in close proximity thereto),
thereby enabling a determination of when the cement slurry 1530
arrives at or near a downhole end of the annulus 26, as illustrated
in FIG. 23c. In an embodiment, pumping of the cement slurry 1530
may be controlled (e.g., slowed and/or terminated) when the data
interrogator incorporated in and/or positioned in close proximity
to the casing shoe 1520 detects the slug 1540 of MEMS sensors 52,
thereby providing for precise placement of the cement slurry into
the annular space while, based upon the design parameters of the
well, likewise optionally allowing for a controlled amount of
cement to be pumped through the float shoe and into the interior of
the casing (or conversely preventing cement from entering into the
interior of the casing). In an embodiment, reverse cementing may be
carried out in accordance with embodiments described in U.S. Pat.
No. 7,357,181, which is hereby incorporated by reference herein in
its entirety.
[0167] In an embodiment, after the pumping of the cement slurry
1530 is terminated, the casing 20 may be lowered in the wellbore 18
until a head 1523 of the valve 1522 makes physical contact with the
bottom 19 of the wellbore 18. The casing 20 may then be lowered
further in opposition to a force of spring 1524 until the valve
head 1523 is seated on a downhole end of the casing shoe 1520. In
this manner, cement slurry 1530 is prevented from further entering
the interior of the casing 20.
[0168] Referring to FIG. 23d, a method 1550 of servicing a wellbore
is described. At block 1552, a cement slurry is pumped down the
wellbore. A plurality of Micro-Electro-Mechanical System (MEMS)
sensors is added to a portion of the cement slurry, for example a
slug of MEMS sensors added to a leading edge of the slurry that is
added to the wellbore prior to a remainder of the cement slurry
and/or a slug of MEMS sensors added to a trailing edge of the
slurry. At block 1554, as the cement slurry is traveling through
the wellbore, positions of the MEMS sensors in the wellbore are
determined along a length of the wellbore, thereby providing a
determination of a corresponding location (e.g., leading and/or
trailing edge) of the cement slurry.
[0169] In embodiments, MEMS sensors having one or more identifiers
associated therewith may be included in the wellbore servicing
composition. By way of non-limiting example, one or more types of
RFID tags, e.g., comprising an RFID chip and antenna, may be added
to wellbore servicing fluids. The RFID tag allows the RFID chip on
the MEMS sensor to power up in response to exposure to RF waves of
a narrow frequency band and modulate and re-radiate these RF waves,
thereby providing information such as a group identifier, sensor
type identifier, and/or unique identifier/serial number for the
MEMS sensors and/or data collected by the MEMS sensors, for example
any combination of the various sensed parameters disclosed herein.
If a data interrogation unit in a vicinity of the MEMS sensor
generates an electromagnetic field in the narrow frequency band of
the RFID tag, then the MEMS sensor can transmit sensor data to the
data interrogator, and the data interrogator can determine that a
MEMS sensor having a specific RFID tag is in the vicinity of the
data interrogator. Again, while various RFID embodiments are
disclosed herein, any suitable technology compatible with and
integrated into the MEMS sensors may be employed to allow the MEMS
sensors to convey information, e.g., one or more identifiers and/or
sensed parameters, to one or more interrogation units.
[0170] In embodiments, MEMS sensors having a first identifier
(e.g., a first type of RFID tag, for example tags exhibiting an "A"
signature) may be added to/suspended in all or a portion of a first
wellbore servicing fluid, and MEMS sensors having a second
identifier (e.g., a second type of RFID tag, for example tags
exhibiting a "B" signature) may be added to/suspended in all or a
portion of a second wellbore servicing fluid. The first and second
wellbore servicing fluids may be added consecutively to a wellbore
in which a casing having regularly longitudinally spaced data
interrogation units attached thereto is situated. As the first and
second wellbore servicing fluids travel through the wellbore, the
data interrogation units interrogate the respective MEMS sensors of
the fluids, thereby obtaining data regarding the indentifier
associated with the MEMS sensor (e.g., the type of RFID tag) and/or
at least one wellbore parameter such as a position of the MEMS
sensors in the wellbore or other sensed parameter (e.g.,
temperature, pressure, etc.). For example, the data interrogation
units may interact with the MEMS sensor as described in relation to
FIGS. 22a-c and 23a-d. As a result, in an embodiment, the positions
of the different types of MEMS sensor (e.g., different types of
RFID tags such as "A" tags and "B" tags) suspended in the two
wellbore servicing fluids may be determined. In addition, using the
aggregated positions of the MEMS sensors having the same and/or
different type of RFID tag, a volume occupied by the first and/or
second wellbore servicing fluids in the wellbore at a specific time
and/or location in the wellbore may be determined.
[0171] In an embodiment, the first and second wellbore servicing
fluids may be substantially the same compositionally, and for
example two or more different types of tags may be used to indicate
different volumetic portions of the same fluid (e.g., a first 100
barrels having "A" tags followed by 500 barrels of "B" tags),
thereby aiding in downhole identification, metering, measuring,
and/or placement of fluids. In an alternative embodiment, the first
and second wellbore servicing fluid may be compositionally
different, and for example different types of tags may be used to
indicate the different types of fluids (e.g., a first fluid such as
cement having "A" tags followed by a second type of fluid such as a
drilling fluid having "B" tags), thereby aiding in downhole
identification, metering, measuring, and/or placement of fluids.
Such embodiments may be further combined, for example a first fluid
having two different types of identifiers ("A" and "B" tags to
denote different volumetric portions), followed by a second,
different fluid having a third type of identifier (e.g., "C" tags)
to denote the different composition or fluid type.
[0172] In an embodiment, MEMS sensors having a third identifier
(e.g., a third type of RFID tag, for example exhibiting a "C"
signature) may be added to/suspended in a third wellbore servicing
fluid and placed in the wellbore. For example, a third wellbore
servicing fluid comprising "C" tags may be placed in the wellbore
prior to, intermittent with, or subsequent to placement of first
and second wellbore servicing fluids into the wellbore, having "A"
and "B" tags, respectively. In an embodiment, the identifier (e.g.,
RFID tag) of the sensors in the third wellbore servicing fluid may
be the same as the identifier (e.g., RFID tag) of the sensors in
the first wellbore servicing fluid (for example a first fluid
having "A" tags followed by a second fluid having "B" tags followed
by a third fluid having "A" tags, wherein the first, second, and
third fluids may be compositionally the same or different) or may
be different from the identifier (e.g., RFID tag) of the sensors in
the first wellbore servicing fluid (for example, a first fluid
having "A" tags followed by a second fluid having "B" tags followed
by a third fluid having "C" tags, wherein the first, second, and
third fluids may be compositionally the same or different).
[0173] The MEMS sensors may employ any suitable power source and/or
transmission technology to convey an associated identifier to the
interrogation units. In an embodiment, the MEMS sensors may be
powered by the data interrogation units. In an alternative
embodiment, the MEMS sensors may be powered by batteries disposed
in the MEMS sensors.
[0174] In an embodiment, instead of adding the MEMS sensors to the
entire first and second wellbore servicing fluids, the MEMS sensors
having the first identifier (e.g., first type of RFID tag) may be
added as a slug to a portion of the first wellbore servicing fluid
added to the wellbore prior to a remainder of the first wellbore
servicing fluid; and the MEMS sensors having the second identifier
(e.g., a second type of RFID) tag may be added as a slug to a
portion of the second wellbore servicing fluid added to the
wellbore prior to a remainder of the second wellbore servicing
fluid. As the wellbore servicing fluids travel through the
wellbore, the positions and MEMS sensors (e.g., RFID tags) in each
slug, and therefore the positions of heads of the wellbore
servicing fluids, may be determined by the data interrogation
units. In an embodiment, the positions of the MEMS sensors having
the second identifier (e.g., second type of RFID tag) may be used
to determine an interface of the first and second wellbore
servicing fluids in the wellbore. While examples of first, second,
and/or third wellbore servicing fluids and associated first, second
and/or third identifiers have been described, it should be
understood that any desirable number of wellbore servicing fluids
and associated identifiers (including more than one identifier type
in a given wellbore servicing fluid type or composition) may be
used to carryout the embodiments disclosed herein.
[0175] Referring to FIG. 23e, a method 1560 of servicing a wellbore
is described. At block 1562, a first wellbore servicing fluid
comprising a plurality of Micro-Electro-Mechanical System (MEMS)
sensors having a first identifier (e.g., a first type of radio
frequency identification device (RFID) tag) is placed into the
wellbore. At block 1564, after placing the first wellbore servicing
fluid into the wellbore, a second wellbore servicing fluid
comprising a plurality of MEMS sensors having a second identifier
(e.g., a second type of RFID tag) is placed into the wellbore. At
block 1566, positions in the wellbore of the MEMS sensors having
the first and second identifiers (e.g., first and second types of
RFID tags) are determined along a length of the wellbore, thereby
providing a determination of a corresponding location (e.g.,
leading and/or trailing edge) of the first and/or second fluids.
The MEMS sensors comprising the first and second identifiers may be
added to all or a portion (e.g., leading and/or trailing edge slug)
of the first and second wellbore servicing fluids, respectively. In
embodiments, the first and second wellbore servicing fluids may be
compositionally the same or different.
[0176] In an embodiment, MEMS sensors having a common or same
identifier (e.g., a common or same type of RFID tag such as an "A"
tag) may be added as slugs to portions of two or more wellbore
servicing fluids added to a wellbore prior to remainders of the
respective two or more wellbore servicing fluids. In embodiments,
the two or more wellbore servicing fluids may be compositionally
the same or compositionally different. In an embodiment, the MEMS
sensor slugs of the respective wellbore servicing fluids may be of
different fluid volumes and/or of different MEMS sensor
loadings/concentrations. As the wellbore servicing fluids travel
through the wellbore, the positions of the MEMS sensors in each
slug may be determined in real time by data interrogation units
spaced at regular intervals along a casing of the wellbore, thereby
providing a determination of a corresponding location (e.g., a
leading and/or trailing edge) of the wellbore servicing fluids. In
addition, in an embodiment, the different volumes and/or different
MEMS sensor loadings of each slug may be detectable as unique
signals by the data interrogation units. Accordingly, positions
(e.g., heads or leading/trailing edges) of each of the wellbore
servicing fluids in the wellbore may be identified using MEMS
sensors having only one identifier (e.g., one type of RFID tag such
as "A" tags). In an embodiment, volumes in the wellbore occupied by
all but the last added wellbore servicing fluid may be determined
using the positions of each MEMS sensor slug in the wellbore.
Furthermore, in an embodiment, three wellbore servicing fluids may
be added to the wellbore in succession, whereby the first and third
wellbore servicing fluids are compositionally the same and the
second wellbore servicing fluid is a spacer fluid.
[0177] Referring to FIG. 23f, a method 1570 of servicing a wellbore
is described. At block 1572, a first wellbore servicing fluid
comprising a plurality of Micro-Electro-Mechanical System (MEMS)
sensors having a first identifier (e.g., a first type of radio
frequency identification device (RFID) tag) is placed into the
wellbore. The MEMS sensors are added to all or a portion of the
first wellbore servicing fluid (e.g., a leading and/or trailing
edge slug of the first wellbore servicing fluid added to the well
bore prior to a remainder of the first wellbore servicing fluid).
At block 1574, after placing the first wellbore servicing fluid
into the wellbore, a second wellbore servicing fluid comprising a
plurality of MEMS sensors having the first identifier (e.g., the
first type of RFID tag is placed into the wellbore). The MEMS
sensors are added to all or a portion of the second wellbore
servicing fluid (e.g., a leading and/or trailing edge of the second
wellbore servicing fluid added to the well bore prior to a
remainder of the second wellbore servicing fluid). In embodiments,
the concentration of the first identifier in the first fluid is
different from the concentration of the first identifier in the
second fluid. In embodiments, the first and second wellbore
servicing fluids may be compositionally the same or different. At
block 1576, positions in the wellbore of the MEMS sensors having
the first identifier (e.g., first type of RFID tag) are determined
along a length of the wellbore, thereby providing a determination
of a corresponding location (e.g., leading and/or trailing edge) of
the first and/or second fluids.
[0178] FIGS. 24a to 24c illustrate a schematic cross-sectional view
of an embodiment of a wellbore parameter sensing system 1600, which
comprises the wellbore 18, the casing 20 situated in the wellbore
18, a plurality of data interrogation units 1610 spaced at regular
or irregular intervals along a length of the casing 20, a float
shoe 1620 situated at a downhole end of the casing 20, and four
wellbore servicing fluids added to the wellbore 18 in succession,
namely, a drilling fluid 1630, a spacer fluid 1640, a cement slurry
1650 and a displacement fluid 1660. In an embodiment, the float
shoe 1620 comprises a poppet valve 1622, which, in a neutral state,
is biased closed by a spring 1624. In addition, the poppet valve
1622 may be opened in opposition to a force applied by spring 1624
when a differential pressure between an interior of the casing 20
and the annulus 26 is sufficiently high.
[0179] In an embodiment, the drilling fluid 1630, the spacer fluid
1640, the cement slurry 1650 and the displacement fluid 1660 are
added to the wellbore within the context of cementing the casing 20
to the wellbore 18. In an embodiment, the drilling fluid 1630
comprises a slug 1632 of MEMS sensors 52 added to the wellbore 18
prior to a remainder of the drilling fluid 1630, the spacer fluid
1640 comprises a slug 1642 of MEMS sensors 52 added to the wellbore
18 prior to a remainder of the spacer fluid 1640, the cement slurry
1650 comprises a slug 1652 of MEMS sensors 52 added to the wellbore
18 prior to a remainder of the cement slurry 1650, and the
displacement fluid 1660 comprises a slug 1662 of MEMS sensors 52
added to the wellbore 18 prior to a remainder of the displacement
fluid 1660. However, in other embodiments, the MEMS sensors 52 may
be mixed and suspended in entire volumes of one or more of the
wellbore servicing fluids added to the wellbore 18. In alternative
embodiments, slugs of MEMS sensors may be added to the trailing
edges of one or more of the fluids 1630, 1640, 1650, and 1660 in
lieu of or in addition to the slugs at the leading edges of the
fluids. In addition, in the present embodiment, the MEMS sensors 52
in all of the slugs 1632, 1642, 1652, 1662 comprise a same
identifier (e.g., a same type of RFID tag such as an "A" tag).
However, in alternative embodiments, the slugs 1632, 1642, 1652,
1662 may comprise MEMS sensors 52 having two or more different
types of identifiers (e.g., two or more different types of RFID
tags such as "A", "B", "C", and "D" tags.). Furthermore, in the
present embodiment, the slugs 1632, 1642, 1652, 1662 are all of
approximately the same volume and MEMS sensor loading. However, in
alternative embodiments, the slugs 1632, 1642, 1652, 1662 may be of
different volumes and/or different MEMS sensor loadings so as to
further identify and distinguish between the heads and interfaces
of the wellbore servicing fluids 1630, 1640, 1650, 1660 added to
the wellbore 18.
[0180] In an embodiment, the drilling fluid 1630, spacer fluid
1640, cement slurry 1650 and displacement fluid 1660 are pumped
down the interior of the casing 20 in succession, in the direction
of arrow 1670. In some embodiments, one or more plugs may be pumped
along with the fluids, for example plugs at the interface of two of
the fluids and providing an additional physical barrier between
said fluid at the interface. For example, a wiper plug may be
pumped behind the cement slurry 1650 and in front of the spacer
fluid 1640 (e.g., the wiper plug positioned proximate ahead of the
MEMS sensor slug 1662). As each wellbore servicing fluid 1630,
1640, 1650, 1660 travels down the casing 20, the data interrogators
1610 in a vicinity/proximity of the respective MEMS sensor slugs
1632, 1642, 1652, 1662 are able to detect the MEMS sensors 52 in
the slugs 1632, 1642, 1652, 1662 and thus identify heads and
interfaces of the wellbore servicing fluids 1630, 1640, 1650, 1660
in the casing 20.
[0181] In an embodiment, as a pressure in the casing 20 increases
due to the pumping of the wellbore servicing fluids 1630, 1640,
1650, 1660 down the casing 20, a pressure differential between the
casing interior and the annulus 26 increases sufficiently to
overcome the force applied by spring 1624 to the poppet valve 1622
and force the valve 1622 open. The drilling fluid 1630 may then
pass through the poppet valve 1622 of the float shoe 1620 in the
direction of arrows 1672 and travel up the annulus 26 in the
direction of arrows 1674, followed by spacer fluid 1640, as shown
in FIG. 24a. As the drilling fluid 1630 and the spacer fluid 1640
travel up the annulus 26, the data interrogation units 1610 in the
vicinity of the slugs 1632 and 1642 detect the MEMS sensors 52 in
the slugs 1632, 1642 and thus determine the location of the heads
and the interface of the drilling fluid 1630 and the spacer fluid
1640 in the annulus 26.
[0182] Referring to FIG. 24b, the displacement fluid 1660 has been
pumped partway down the casing 20, the cement slurry 1650 is
partially in the casing 20 and partially in the annulus 26, the
spacer fluid 1640 is completely in the annulus 26 and most of the
drilling fluid 1630 has exited the annulus 26. As the spacer fluid
1640 and cement slurry 1650 travel up the annulus 26, the data
interrogation units 1610 detect the location of their respective
heads and their interface via the MEMS sensors located in slugs
1642 and 1652. Similarly, as the displacement fluid 1660 travels
down the casing 20, the data interrogation units 1610 detect a
location of the head of the displacement fluid 1660 via the MEMS
sensors located in slug 1662.
[0183] Referring now to FIG. 24c, the spacer fluid 1640 has been
pumped out of the annulus 26, the cement slurry 1650 has been
pumped nearly all the way up the annulus 26, and the displacement
fluid 1660 has been pumped nearly all the way down the casing 20,
such that the MEMS sensor slug 1662 at the head of the displacement
fluid 1660 is situated proximate to the float shoe 1620. In an
embodiment, a data interrogation unit may be incorporated/integral
with and/or located proximate to the float shoe 1620 for the
purpose of detecting the MEMS sensor slug 1662 at the head of the
displacement fluid 1660. However, in an alternative embodiment, the
data interrogation unit may be incorporated in a float collar
situated proximate uphole from the float shoe 1620. When the sensor
slug 1662 is detected at or near the float shoe 1620, pumping of
the wellbore servicing fluids may be controlled (e.g., slowed
and/or terminated) to provide for precise placement of the cement
slurry into the annular space while, based upon the design
parameters of the well, likewise optionally allowing for a
controlled amount of cement to remain in the casing proximate the
float collar or optionally allowing for removal of substantially
all of the cement from the interior of the casing. In an
embodiment, pumping is controlled so as to prevent the displacement
fluid from entering the annulus 26 and possibly degrading the
cement slurry 1650 near a base of the annulus 26. When pumping
ceases, the pressure in the interior of the casing 20 decreases,
thereby allowing the valve 1622 to close. Additionally or
alternatively, in an embodiment, when a data interrogation unit
1610 located at a desired/known position uphole (e.g., the position
most proximate to the earth's surface 16) detects the MEMS sensor
slug 1652 at the head of the cement slurry 1650, then an operator
may conclude that the cement slurry 1650 has filled most or all of
the annulus 26 and may be allowed to cure.
[0184] In an embodiment, MEMS sensors may be added to a hydraulic
fracturing fluid comprising one or more proppants. The fracturing
fluid may be introduced into the wellbore and into one or more
fractures situated in the wellbore and extending outward into the
formation. At least a portion of the MEMS sensors may be deposited,
along with the proppant or proppants, into the fracture or
fractures and remain therein. In an embodiment, the MEMS sensors
situated in the fracture or fractures may measure at least one
parameter associated with the fracture or fractures, such as a
temperature, pressure, a stress, a strain, a CO.sub.2
concentration, an H.sub.2S concentration, a CH.sub.4 concentration,
a moisture content, a pH, an Na.sup.+ concentration, a K.sup.+
concentration or a Cl.sup.-concentration. In an embodiment, the
presence of MEMS sensors deposited in one or more fractures
facilitates the mapping of the fracture. For example, referring to
FIG. 19, a fracturing fluid containing MEMS sensors may be pumped
into fractures such as represented by fissures 58 and 60 extending
into formation 62 and the MEMS sensors deposited therein. Data
interrogation units 150 may then provide a map of the fracture
complexity in a manner similar to mapping the geometry of the
wellbore (e.g., locating constrictions, expansions, etc.) as
disclosed herein, for example in reference annular mapping
embodiment of FIGS. 17-21. Furthermore, mobile data interrogation
units may be used in addition to or in lieu of the fixed data
interrogation units 150 shown in FIG. 19. e.g., a data
interrogation unit located on a fracturing service workstring, for
example located proximate an end of a coiled tubing workstring
employed in a fracturing operation.
[0185] In an embodiment, the MEMS sensors in a fracture measure
moisture content. When the moisture content exceeds a threshold
value, it may be concluded that the fracture is producing water,
and the fracture may be plugged or treated so as to no longer
produce water. In an embodiment, the MEMS sensors in a fracture
measure CH.sub.4 concentration. If the CH.sub.4 concentration
exceeds a threshold value, it may be concluded that the fracture is
producing methane. In an embodiment, the MEMS sensors in a fracture
measure a stress or mechanical force. If the stress or mechanical
force exceeds a threshold value, it may be concluded that the
fracture is producing sand, and the fracture may be treated so as
to no longer produce sand.
[0186] Referring to FIG. 24d, a method 1680 of servicing a wellbore
is described. At block 1682, a plurality of MEMS sensors is placed
in a fracture that is in communication with the wellbore, for
example via pumping a fracturing fluid comprising MEMS sensors into
the fracture, reducing pressure, and allowing the MEMS sensors
(along with proppant) to be deposited in the formation. The MEMS
sensors are configured to measure at least one parameter associated
with the fracture, and at block 1684, the at least one parameter
associated with the fracture is measured. In an embodiment, the
MEMS sensors provide positional data with respect to one or more
data interrogation units located at a known position (e.g., located
at casing collars at known depths within the wellbore), and thereby
provide information about the geometry and layout of fractures
within the formation. For example, within the sensing or mapping
range, the data interrogation units are operable to sense the
presence of various MEMS sensors in relation to the unit, and thus
can create a mathematical representation of MEMS sensor presence,
velocity, location, concentration, and/or identity (e.g., a
particular sensor or group of sensors having a unique identifier or
I.D. number) in relation to the position of a given unit 150, along
with other parameters such as moisture content, CH.sub.4
concentration, mechanical measurements (stress, strain, forces,
etc.), ion concentration, acidity, pH, temperature, pressure, etc.
Such information can be provided in real time, and an ongoing
fracturing job may be adjusted in response to information provided
by the MEMS sensors located in the fracture. For example, the MEMS
sensors may provide a real time snapshot of fracture development,
complexity, orientation, lengths, etc. that may be analyzed and
used to further control the fracturing operation. At block 1686,
data regarding the at least one parameter associated with the
wellbore, formation, and/or fracture is transmitted from the MEMS
sensors to an exterior of the wellbore in accordance with any
embodiment disclosed herein, e.g., FIGS. 5-16. At block 1688, the
data is processed.
[0187] In an alternative embodiment, the detection of MEMS sensors
in one or more fractures is used to control a wellbore servicing
operation when fracturing is not desired. For example, in certain
wellbore servicing operations, such as during drilling and/or
cementing, fracturing may be undesirable as leading to detrimental
loss of fluids into the formation. As described above, MEMS sensors
can be added to a wellbore servicing fluid (e.g., drilling fluid
and/or cement slurry) to detect movement and/or placement of the
MEMS into the formation via movement of the fluid, and where such
movement of the fluid into the formation is undesirable, one or
more process parameters (e.g., flow rate, pressure, etc.) may be
controlled (e.g., in real time) to alter the servicing treatment
and reduce, stop, or eliminate the undesirable formation of
fractures and resultant loss of servicing fluid to the formation.
Thus, MEMS sensors may be used in a variety of wellbore servicing
fluid to control fracturing of the surrounding formation, to
desirably induce/promote and/or inhibit/prevent formation of
fractures as appropriate for a given service type.
[0188] In an embodiment, a plurality of Micro-Electro-Mechanical
System (MEMS) sensors are placed in a wellbore composition, the
wellbore composition is placed in a wellbore, and the MEMS sensors
are used to monitor and detect movement in the wellbore and/or the
surrounding formation. The data may be obtained from the MEMS
sensors according to any of the embodiments disclosed herein (e.g.,
one or more mobile data interrogators tripped into and out of the
wellbore and/or fixed data interrogators positioned within the
wellbore), and may be further communicated/transmitted to/from or
within the wellbore via any of the embodiments disclosed herein.)
For example, the MEMS sensors may be in a sealant composition that
is placed within an annular casing space in the wellbore and
wherein the movement comprises a relative movement between the
sealant composition and the adjacent casing and/or wellbore wall.
In other words, the MEMS sensors detect slippage or shifting of the
cement sheath, the casing, and/or the wellbore wall/formation
relative to one another. Additionally or alternatively, at least a
portion of the wellbore composition comprising the MEMS flows into
the surrounding formation and movement in the formation is
monitored/detected. For example, cracks, fissures, shifts,
collapses, etc. of the formation may be detected over the life of
the wellbore via the MEMS sensors. Such movement may be detected
via the motion and/or orientation sensing capabilities (e.g.,
accelerometers, x-y-z axis orientation, etc.) of the MEMS sensors
as described herein. In particular, data collected from the MEMS
sensors may be compared over successive monitoring or surveying
intervals to detect movement and associated patterns. In
particular, such movement may be correlated with production rates
over the life of the well to help in optimizing production from the
well both in terms of rate of production as well as total
production over the life of the well. For example, in response to
the detection of motion in the formation (e.g., a shift in the
formation), one or more operating parameters of the wellbore may be
adjusted, for example the production rate of the wellbore (e.g.,
the rate of production of hydrocarbons from the wellbore), and such
adjustments may extend an expected operating life of the
wellbore.
[0189] In an embodiment, MEMS sensors may be mixed into a sealant
composition (e.g. cement slurry) that is placed into the annulus 26
between a wall of the wellbore 18 and the casing 20. In
embodiments, the sealant composition may be pumped down the
drillstring/casing and up the annulus in a conventional cementing
service, or alternatively the sealant composition may be pumped
down the annulus in a reverse cementing job. The MEMS sensors may
be used to monitor the sealant composition and/or the annular space
for the presence and/or concentration of gas, water, or both,
including but not limited to monitoring for the presence of
corrosive materials, such as corrosive gas (e.g., acid gases such
as hydrogen sulfide, carbon dioxide, etc.) and/or corrosive liquids
(e.g., acid). Accordingly, the MEMS sensors may be configured to
measure a concentration of a water and/or gas in the cement slurry,
such as CH.sub.4, H.sub.2S, or CO.sub.2, prior to the cement
setting. A degree of gas and/or water influx into the cement slurry
may be determined using the gas and/or water concentration measured
by the MEMS sensors. In particular, the presence of MEMS in the
cement slurry may aid in identification of any undesirable inflow
or channeling formed by gas migrating or flowing into the cement
slurry prior to setting of the cement, as such gas and/or water
inflow may be adverse to the integrity of and zonal isolation
provided by the annular sheath of set cement. Furthermore, MEMS
sensors fixed in the set cement may also further aid in the
detection of any such flow channels or other defects via annular
mapping of the cement sheath as described herein. The presence
and/or movement of annular water and/or gas as detected by MEMS
distributed along a portion of the set cement sheath may be
indicative of a loss or potential loss of zonal isolation, and
remedial actions such as a squeeze job may be required to restore
zonal isolation and prevent further gas migration within the
wellbore.
[0190] In a further embodiment, the above-mentioned cement slurry
comprising MEMS sensors is allowed to cure so as to form a cement
sheath. The MEMS sensors, which are distributed throughout the
cross section of the cement sheath, may be configured and/or
operable to measure a water and/or gas presence and/or
concentration in the cement sheath. Again, the MEMS sensors may be
used to monitor the set sealant composition and/or the annular
space, for example at periodic monitoring or service intervals over
an expected service life of the wellbore, for the presence and/or
concentration of gas, water, or both, including but not limited to
monitoring for the presence of corrosive materials, such as
corrosive gas (e.g., acid gases such as hydrogen sulfide, carbon
dioxide, etc.) and/or corrosive liquids (e.g., acid). If a water
and/or gas is present in the wellbore in a vicinity of a region of
the cement sheath, MEMS sensors situated in the region of the
cement sheath, for example in an interior of the cement sheath
and/or at an interface of the cement sheath and the wellbore, may
measure the presence/concentration of the water and/or gas at
corresponding locations in the interior of the cement sheath and/or
at the cement sheath/wellbore interface. In an embodiment, an
integrity (e.g., structural integrity as effective to
provide/maintain zonal isolation) of the region of the cement
sheath may be determined using the presence/concentration of the
water and/or gas measured by the MEMS sensors in the interior of
the cement sheath. The region of the cement sheath may be
determined to be integral (e.g., uncompromised and of acceptable
structural integrity) if the concentration of the water and/or gas
measured by the MEMS sensors in the interior of the cement sheath
is less than a threshold value, for example less than a
concentration of gas measured at the cement sheath/wellbore
interface, which indicates that water and/or gas is not penetrating
from an exterior surface of the cement sheath into an interior
location.
[0191] In embodiments, the MEMS sensors in the unset sealant
composition (e.g., cement slurry) and/or in the a set sealant
composition (e.g., set cement forming a sheath) the MEMS sensors
may be interrogated by running an interrogator into the wellbore,
for example during and/or immediately after the cementing operation
and/or at service interval over the life of the wellbore. In
alternative embodiments, the MEMS sensors are interrogated via data
interrogators permanently located in the wellbore.
[0192] In embodiments, the MEMS sensors in the unset sealant
composition (e.g., cement slurry) and/or in the a set sealant
composition (e.g., set cement forming a sheath) detect the presence
and/or concentration of water, gas, or both, including but not
limited to monitoring for the presence of corrosive materials, such
as corrosive gas (e.g., acid gases such as hydrogen sulfide, carbon
dioxide, etc.) and/or corrosive liquids (e.g., acid). In such
embodiments, an operator of a wellbore servicing operation, an
field operator, or other person responsible for monitoring the
wellbore may be signaled as to the detected gas and/or water (e.g.,
an alarm or alert may be signaled or activated). The MEMS sensors
may be used to provide a location in the wellbore corresponding to
the detection of gas and/or water. In an embodiment (for example,
an emergency or urgent response), at least one device is activated
to prevent fluid flow out of the well in response to the detection
of gas and/or water, and in particular during a cementing operation
where the cement has not yet hardened and set. Such devices may
include emergency shut off valves (e.g., sub-surface safety
valves), blow out preventers, and the like. The activation of such
devices may be automatic and/or manual in response to the detection
signal and/or alarm. Upon establishing and/or confirming control of
the wellbore (e.g., the wellbore is safely contained and/or shut
in), one or more remedial actions may be performed in response to
the detection of gas and/or water. For example, a tool may be
lowered into the wellbore proximate the location of the detected
gas and/or water, and the surrounding area may be surveyed for
damage such as cracks in the cement sheath, corrosion of the
casing, etc. to determine the integrity thereof. Upon assessing the
nature and extent of damage, remedial services may be performed.
For example, the area may be patched by placing additional sealant
composition into the damaged area (e.g., squeezing cement into
damaged areas such as flow channel, cracks, etc.). Additionally or
alternatively, a section of damaged casing may be replaced or
repaired, for example by cutting out and replacing the damaged
section or placing a reinforcing casing or liner within the damaged
portion. Such remedial actions may extend the expected service life
of the wellbore.
[0193] In alternative embodiments, the MEMS sensors in the a set
sealant composition (e.g., set cement forming a sheath) detect the
presence and/or concentration of water, gas, or both, including but
not limited to monitoring for the presence of corrosive materials,
such as corrosive gas (e.g., acid gases such as hydrogen sulfide,
carbon dioxide, etc.) and/or corrosive liquids (e.g., acid), and in
response one or more operating parameters of the wellbore are
adjusted, for example the production rate of the wellbore (e.g.,
the rate of production of hydrocarbons from the wellbore). Example
of operating conditions or parameters further include temperature,
pressure, production rate, length of service interval, or any
combination thereof. Adjusting one or more operating conditions of
the wellbore, in addition to or in lieu of one or more remedial
actions, may extend the expected service life of the wellbore.
[0194] In an embodiment, the MEMS sensors may be mixed into a
sealant composition (e.g. cement slurry) that is placed into the
annulus 26 between a wall of the wellbore 18 and the casing 20 in a
wellbore associated with carbon dioxide injection, for example a
carbon dioxide injection well used to sequester carbon dioxide. The
MEMS sensors may be used to detect leaks in such wells. For
example, the detection of carbon dioxide in an annular space in the
wellbore may indicate that the carbon dioxide injection well has
lost zonal integrity or otherwise is leaking. Accordingly, remedial
actions may be taken as described above to repair the leaks and
restore integrity. Additionally or alternatively, such remedial
actions may be taken to work-over pre-existing wells, for example
to retrofit older wells that may no longer be economically viable
for hydrocarbon production, and thereby render such wells suitable
for carbon dioxide injection. Such wells would be useful for
sequestering carbon dioxide from large scale commercial sources for
green house gas reduction purposes.
[0195] FIG. 25 illustrates an embodiment of a wellbore parameter
sensing system 1700 comprising the wellbore 18, the casing 20
situated in the wellbore 18, a plurality of data interrogation
units 1710 spaced along a length of the casing 20, a processing
unit 1720 situated at an exterior of the wellbore 18, and a cement
slurry placed into the annulus 26 between the wellbore 18 and the
casing 20 and allowed to cure to form a cement sheath 1730. In an
embodiment, the data interrogation units 1710 may be powered by
rechargeable batteries or a power supply situated at the exterior
of the wellbore 18, or otherwise as disclosed in various
embodiments herein.
[0196] In an embodiment, the cement sheath 1730 comprises MEMS
sensors 52, which are configured to measure at least one wellbore
parameter, e.g., a spatial position of the MEMS sensors 52 with
respect to the various data interrogation units 1710 and/or the
casing 20 (e;g., data interrogation units mounted at known
locations such as casing collars). The MEMS sensors 52 may be
suspended in, and distributed throughout, the cement slurry and the
cured cement sheath 1730. The MEMS sensors 52 may be passive
sensors, i.e., powered by electromagnetic pulses emitted by the
data interrogation units 1710, or active sensors, i.e., powered by
batteries situated inside the MEMS sensors 52 or otherwise powered
by a downhole power source. In an embodiment, the data
interrogation units 1710 may interrogate the MEMS sensors 52 and
receive from the MEMS sensors 52 data regarding, e.g., the spatial
position of the MEMS sensors 52, and transmit the data to the
processing unit 1720 for processing. In an embodiment, the data
interrogation units 1710 may transmit the sensor data to the
processing unit 1720 via a data line that runs along the casing,
for example as shown in FIGS. 5, 7, and 9. In an alternative
embodiment, the data interrogation units 1710 may transmit the
sensor data wirelessly to neighboring data interrogation units 1710
and up the casing 20 to the processing unit 1720, for example as
shown in FIGS. 6, 8, and 10. While fixed data interrogation units
1710 are shown, it should be understood that a mobile data
interrogation units (for example, for examples unit 40 of FIG. 2,
unit 620 of FIG. 8, and unit 740 of FIG. 9) may be disposed and
moved within the wellbore to further aid in obtaining and/or
processing data associated with cross-sectional views of the
annulus, cement sheath, and/or formation.
[0197] In an embodiment, the processor 1720 may be configured to
divide the wellbore 18 into a plurality of cross-sectional slices
of a specified width that are situated along a length of the
wellbore 18. The width of each slice may be about 0.1 cm to 10 cm,
alternatively about 0.5 cm to 5 cm, alternatively 0.5 cm to 1 cm.
In an embodiment, the processor 1720 is configured to aggregate
planar coordinates of the positions of the MEMS sensors 52 in each
cross-sectional slice and plot the planar coordinates of the
positions of the MEMS sensors 52 in each cross-sectional slice so
as to approximate cross-sections of the cement sheath 1730 in the
annulus 26, along the length of the casing 20. In an embodiment,
the planar coordinates may comprise Cartesian coordinates, in which
a center of a casing cross-section serves as an origin. In a
further embodiment the planar coordinates may comprise polar
coordinates, in which a center of a casing cross-section serves as
an origin.
[0198] In embodiments, the cross-sectional slices of the wellbore
may be used to determine an integrity of the cement sheath 1730
along the length of the casing 20. As the MEMS sensors 52 are
distributed throughout the cement sheath 1730, the cross-sectional
slices may be used to determine an extent of cement coverage in the
annulus 26 and/or a cross-sectional shape of the annulus 26. In an
embodiment, in cross-sectional slices in which no MEMS sensors 52
are situated in specific regions outside of the casing 20, the
presence of a void in the cement sheath 1730 and/or a constriction
in the annulus 26 may be determined. In an embodiment, in
cross-sectional slices in which MEMS sensor coordinates extend
beyond a boundary at which a wall of the wellbore 18 is thought to
be situated, it may be concluded that the wellbore 18 is washed out
and/or contains a significant fracture or fractures or permeable
regions through which cement has migrated. In some embodiments, the
MEMS sensors may extend from the wellbore into the formation, and
likewise the cross-sectional slices may provide information
regarding the formation, for example cross-sectional shapes of
fractures/fissures such as shown in FIGS. 19 and 20. For example, a
cemented wellbore may be perforated, a fluid (e.g., fracturing
fluid) comprising MEMS sensors may be pumped into the formation
(e.g., via the perforations and/or fractures), and cross-sectional
slices taken of the treated portion of the wellbore. In a further
embodiment, in cross-sectional slices in which the mapped planar
coordinates of the MEMS sensors 52 form an approximately annular
shape without voids, it may be concluded that the cement sheath
1730 is in good condition in regions corresponding to these
cross-sectional slices.
[0199] FIG. 26a, FIG. 26b and FIG. 26c illustrate schematic
cross-sectional views of the wellbore 18 taken at lines A-A, B-B
and C-C, respectively. As is apparent from FIG. 26a, the cement
sheath 1730 contains a void 1732 at which a strength or structural
integrity of the cement sheath 1730 may be compromised.
Accordingly, remedial action such as secondary cementing may be
required to eliminate the void 1732. In addition, as is apparent
from FIG. 26b, a region of the annulus 26 through which line B-B
travels is devoid of cement. In this instance, the presence of
drill cuttings and/or a ledge and/or a build-up of filter cake may
be concluded, and, if necessary, appropriate remedial action may be
undertaken. Furthermore, as is apparent from FIG. 26c, the
cross-sectional slice of the wellbore 18 taken at line C-C has a
smooth, unbroken annular shape. Accordingly, it may be concluded
that the cement sheath 1730 is in good condition at this
cross-sectional slice. Accordingly, the use of MEMS sensors in a
wellbore servicing fluid, including but not limited to a cement
composition, may aid in an assessment of the wellbore, including
providing information regarding annular condition/shapes (e.g.,
FIG. 18), formation condition/shapes (e.g., FIG. 20), cement sheath
condition/shapes (e.g., FIG. 26), and other downhole regions or
conditions as would be apparent based upon the disclosure
herein.
[0200] Referring to FIG. 26d, a method 1750 of servicing a wellbore
is described. At block 1752, a plurality of
Micro-Electro-Mechanical System (MEMS) sensors is placed in a
cement slurry. At block 1754, the cement slurry is placed in an
annulus disposed between a wall of the wellbore and a casing
situated in the wellbore. At block 1756, the cement slurry is
allowed to cure to form a cement sheath. At block 1758, spatial
coordinates of the MEMS sensors with respect to one or more known
locations in the wellbore are determined (e.g., with respect to
data interrogators spaced along the casing, for example at casing
collars). At block 1760, planar coordinates of the MEMS sensors are
mapped in a plurality of cross-sectional planes spaced along a
length of the wellbore. Furthermore, one or more downhole
conditions (e.g., a health or maintenance condition/state of the
wellbore, formation, cement sheath, etc.) may be determined based
upon the mapped cross-sectional planes (e.g., cross-sectional
representations of the wellbore, formation, cement sheath, etc.).
If appropriate, one or more remedial actions (e.g., servicing
operations such as squeeze jobs, etc.) may be carried out in the
area or region of the wellbore displaying a need there for based
upon analysis of the cross-sectional representations. In
embodiments, the cross-sectional analysis is performed in
accordance with a service or inspection interval of the wellbore,
and may further more comprise one or more mobile interrogation
units (in addition to or in lieu of the fixed data interrogation
units 1710 placed into the wellbore (e.g., via wireline or coiled
tubing) during such services or inspections.
[0201] In embodiments, for the purpose of measuring wellbore
parameters, MEMS sensors may not only be mixed with and suspended
in wellbore servicing fluids (for example, as disclosed in the
embodiments of FIGS. 5-26), but may also be integral with wellbore
servicing equipment and tools using, for example, contained or
housed within the tool and/or molded or formed as a part of the
tool formed of plastic or a composite resin material. In an
embodiment, the tool houses a fluid (e.g., a hydraulic fluid)
within space located in the tool (e.g., a fluid reservoir), and the
fluid further comprises MEMS sensors. In addition or alternatively,
data interrogation units may be molded onto wellbore servicing
equipment and tools using, for example, a composite resin material.
In embodiments, the composite resin material may comprise an epoxy
resin. In further embodiments, the composite resin material may
comprise at least one ceramic material. For example, the composite
material may comprise a ceramic based resin including, but not
limited to, the types disclosed in U.S. Patent Application
Publication Nos. US 2005/0224123 A1, entitled "Integral
Centraliser" and published on Oct. 13, 2005, and US 2007/0131414
A1, entitled "Method for Making Centralizers for Centralising a
Tight Fitting Casing in a Borehole" and published on Jun. 14, 2007.
For example, in some embodiments, the resin material may include
bonding agents such as an adhesive or other curable components. In
some embodiments, components to be mixed with the resin material
may include a hardener, an accelerator, or a curing initiator.
Further, in some embodiments, a ceramic based resin composite
material may comprise a catalyst to initiate curing of the ceramic
based resin composite material. The catalyst may be thermally
activated. Alternatively, the mixed materials of the composite
material may be chemically activated by a curing initiator. More
specifically, in some embodiments, the composite material may
comprise a curable resin and ceramic particulate filler materials,
optionally including chopped carbon fiber materials. In some
embodiments, a compound of resins may be characterized by a high
mechanical resistance, a high degree of surface adhesion and
resistance to abrasion by friction.
[0202] In embodiments, wellbore servicing equipment or tools have
MEMS sensors integrated therein may be formed from one or more
composite materials. A composite material comprises a heterogeneous
combination of two or more components that differ in form or
composition on a macroscopic scale. While the composite material
may exhibit characteristics that neither component possesses alone,
the components retain their unique physical and chemical identities
within the composite. Composite materials may include a reinforcing
agent and a matrix material. In a fiber-based composite, fibers may
act as the reinforcing agent. The matrix material may act to keep
the fibers in a desired location and orientation and also serve as
a load-transfer medium between fibers within the composite.
[0203] The matrix material may comprise a resin component, which
may be used to form a resin matrix. Suitable resin matrix materials
that may be used in the composite materials described herein may
include, but are not limited to, thermosetting resins including
orthophthalic polyesters, isophthalic polyesters, phthalic/maelic
type polyesters, vinyl esters, thermosetting epoxies, phenolics,
cyanates, bismaleimides, nadic end-capped polyimides (e.g.,
PMR-15), and any combinations thereof. Additional resin matrix
materials may include thermoplastic resins including polysulfones,
polyamides, polycarbonates, polyphenylene oxides, polysulfides,
polyether ether ketones, polyether sulfones, polyamide-imides,
polyetherimides, polyimides, polyarylates, liquid crystalline
polyester, and any combinations thereof.
[0204] In an embodiment, the matrix material may comprise a
two-component resin composition. Suitable two-component resin
materials may include a hardenable resin and a hardening agent
that, when combined, react to form a cured resin matrix material.
Suitable hardenable resins that may be used include, but are not
limited to, organic resins such as bisphenol A diglycidyl ether
resins, butoxymethyl butyl glycidyl ether resins, bisphenol
A-epichlorohydrin resins, bisphenol F resins, polyepoxide resins,
novolak resins, polyester resins, phenol-aldehyde resins,
urea-aldehyde resins, furan resins, urethane resins, glycidyl ether
resins, other epoxide resins, and any combinations thereof.
Suitable hardening agents that can be used include, but are not
limited to, cyclo-aliphatic amines; aromatic amines; aliphatic
amines; imidazole; pyrazole; pyrazine; pyrimidine; pyridazine;
1H-indazole; purine; phthalazine; naphthyridine; quinoxaline;
quinazoline; phenazine; imidazolidine; cinnoline; imidazoline;
1,3,5-triazine; thiazole; pteridine; indazole; amines; polyamines;
amides; polyamides; 2-ethyl-4-methyl imidazole; and any
combinations thereof.
[0205] The fibers may lend their characteristic properties,
including their strength-related properties, to the composite.
Fibers useful in the composite materials used to form a collar
and/or one or more bow springs may include, but are not limited to,
glass fibers (e.g., e-glass, A-glass, E-CR-glass, C-glass, D-glass,
R-glass, and/or S-glass), cellulosic fibers (e.g., viscose rayon,
cotton, etc.), carbon fibers, graphite fibers, metal fibers (e.g.,
steel, aluminum, etc.), ceramic fibers, metallic-ceramic fibers,
aramid fibers, and any combinations thereof.
[0206] FIG. 27a illustrates an embodiment of a wellbore parameter
sensing system 1800, which comprises the wellbore 18, the casing 20
situated in the wellbore 18, a plurality of data interrogation
units 1810 attached to the casing 20 and spaced along a length of
the casing 20, a processing unit 1820 situated at an exterior of
the wellbore 18, and a plug 1830. In an embodiment, the plug 1830
is a wiper plug configured to be pumped down the casing 20 for the
purpose of removing residues of a wellbore servicing fluid from an
inner wall of the casing 20, typically employed in a wellbore
cementing operation wherein wiper plugs are deployed in front of
and/or behind a cement slurry that is pumped downhole. While
various embodiments herein refer to wiper plugs, it is to be
understood that other types of plugs or pumpable members may be
combined with MEMS sensors, for example balls, darts, etc., and
employed in various other wellbore servicing operations or
functions such as operating valves, sleeves, etc., where the MEMS
sensors may be used to verify the location of the plug or pumpable
member (e.g., to verify that if/when it has landed or seated
properly). In an embodiment, the data interrogation units 1810 may
be powered by rechargeable batteries or a power supply situated at
the exterior of the wellbore 18 or by any other downhole power
supply.
[0207] In an embodiment, the plug 1830 may comprise MEMS sensors
1840, which are configured to measure at least a vertical position
of the MEMS sensors 1840 (and correspondingly the location of the
plug 1830) in the casing 20 and a pressure exerted on the MEMS
sensors 1840 (and correspondingly a pressure exerted on the plug
1830). In an embodiment, the MEMS sensors 1840 may be molded onto a
downhole end (e.g., nose) of the plug 1830, for example a wiper
plug that is configured to mate with a float collar 1850 situated
near a downhole end of the casing 20. In an alternative embodiment,
the MEMS sensors 1840 may be incorporated in a material of which
the plug 1830 is made and situated at the downhole end of the plug
1830 such that the MEMS sensors are in proximity to a seat or other
member that receives or mechanically interacts with the plug 1830.
In other embodiments, the MEMS sensors 1840 may be housed by,
coupled to, or otherwise integral with the plug 1830.
[0208] In operation, in an embodiment, the plug 1830 (e.g., a wiper
plug) may be pumped down the casing 20 in the direction of arrow
1832 by pumping a displacement fluid down the casing 20, directly
in back of the plug 1830. As the plug 1830 travels down the casing
20, data interrogation units 1810 nearest to the MEMS sensors 1840
in the plug 1830 interrogate the MEMS sensors 1840. In response to
being interrogated, the MEMS sensors 1840 may transmit to the data
interrogation units 1810 data regarding at least the vertical
position of the MEMS sensors 1840 in the casing 20 and the pressure
exerted on the MEMS sensors 1840. In an embodiment, the data
interrogation units 1810 may then transmit the sensor data to the
processing unit 1820 via a data line that runs along the casing or
by other communication means or networks (e.g., wireless networks
and/or telemetry) as disclosed herein. For example, the data
interrogation units 1810 may transmit the sensor data wirelessly to
neighboring data interrogation units 1810 (and/or via a MEMS sensor
network where one or more wellbore servicing fluids, e.g., a cement
composition, comprises MEMS sensors and/or up the casing 20) to the
processing unit 1820.
[0209] In an embodiment, when the plug 1830 (e.g., a wiper plug)
lands on a seat or receptacle such as the float collar 1850, the
pressure exerted on the MEMS sensors 1840 situated at the downhole
end of the wiper plug 1830 will increase sharply due to a reaction
force applied to the wiper plug 1830 by the float collar 1850. In
response to the pressure increase detected by the MEMS sensors and
communicated to the surface, pumping of the displacement fluid
behind the wiper plug 1830 may be controlled (e.g., slowed or
terminated). In an embodiment, the pumping of the displacement
fluid may be terminated when the pressure exerted on the MEMS
sensors 1840 reaches a threshold value of about 200 psi to about
3000 psi depending upon depth of the well.
[0210] Referring to FIG. 27b, a method 1860 of servicing a wellbore
is described. At block 1862, a wellbore servicing fluid is placed
downhole. For example, a cement slurry is pumped down a casing
situated in the wellbore and up an annulus situated between the
casing and a wall of the wellbore. At block 1864, a plug comprising
MEMS sensors is placed downhole. For example, a wiper plug
comprising MEMS sensors is pumped down the casing. In an
embodiment, the wiper plug comprises MEMS sensors at a downhole end
of the wiper plug configured to engage with a float collar that is
coupled to the casing and situated proximate to a downhole end of
the casing. The MEMS sensors are configured to measure pressure
and/or location/position within the wellbore, and correspondingly
provide pressure and/or location information for the plug. At block
1866, pumping of the plug is discontinued when a pressure measured
by the MEMS sensors exceeds a threshold value, for example as a
result of the plug coming into contact with or engaging a seat
(e.g., the wiper plug seating on the float collar).
[0211] FIG. 28a illustrates an embodiment of a wellbore parameter
sensing system 1900, which comprises the wellbore 18, the casing 20
situated in the wellbore 18, a plurality of MEMS sensor strips 1910
attached to and/or housed within the casing 20 and spaced along a
length of the casing 20, a processing unit 1920 situated at an
exterior of the casing, and a plug 1930 situated inside of the
casing 20. In an embodiment, the MEMS sensor strips 1910 comprise a
composite resin material, with which MEMS sensors 1912 are mixed,
and which may be molded to the casing 20, for example to an
interior and/or outer wall of the casing or within a hollow or void
space defined by the casing or a component thereof (e.g., a pocket
or void space within a casing collar). In an embodiment, the MEMS
sensor strips 1910 are located in grooves, recessions, scallops,
channels or the like on the interior wall of the casing and form a
flush interface with the interior wall of the casing such that the
interior diameter of the casing is not adversely affected (e.g.,
roughened, restricted, etc.) by the presence of the MEMS sensor
strips 1910. In an embodiment as shown in FIG. 28a, the MEMS sensor
strips 1910 may be embedded in grooves 1914 in the inner wall of
the casing 20 so as not to protrude from the inner wall of the
casing 20. In an embodiment, the MEMS sensor strips 1910 may be
mounted flush with the inner wall of the casing 20. In a further
embodiment, the MEMS sensor strips 1910 may be attached to casing
collars. The MEMS sensors 1912 may be passive sensors or active
sensors and may be configured to measure at least one wellbore
parameter, e.g., a vertical position of the MEMS sensors 1912 along
the casing 20 or an ambient condition (e.g., environmental
condition) within the wellbore.
[0212] In an embodiment, a plug 1930 (e.g., a wiper plug) may
comprise a data interrogation unit 1940, which is configured to
interrogate MEMS sensors 1912 in a vicinity of the data
interrogation unit 1940. The data interrogation unit 1940 may be
molded to the wiper plug 1930 using a composite resin material or
may be otherwise housed by, coupled to, or integral with the plug
1930. In an embodiment, the data interrogation unit 1940 may be
powered by a rechargeable battery, for example a lithium ion
battery. The battery may be charged prior to and/or after placement
of the data interrogation unit into the wellbore. For example, a
battery charger (e.g., inductive charger) may be lowered into the
wellbore periodically to charge batteries associated with the data
interrogation units and/or the MEMS sensors (e.g., active sensors).
In an embodiment, the battery is capable of powering the data
interrogation units for at least 1, 2, 3, or 4 weeks. In an
embodiment, the data interrogation unit 1940 is powered by
transport of the plug 1930 though the wellbore, for example via
fluid flow through the plug driving a power generator. In a further
embodiment, the data interrogation unit 1940 may be powered by a
wireline run between the data interrogation unit 1940 and a power
supply situated at the exterior of the wellbore.
[0213] In operation, the plug 1930 may be pumped down the casing by
pumping a displacement fluid into and down the casing 20 directly
in back of the plug 1930. As the plug 1930 nears and passes the
MEMS sensor strips 1910, the data interrogation unit 1940
interrogates the MEMS sensors 1912 in the respective strips 1910
and receives data from the MEMS sensors 1912 regarding at least the
vertical position of the MEMS sensors 1912 in the casing 20, and
correspondingly the position of the plug 1930 in the wellbore. For
example, as the plug 1930 passes through the wellbore, the data
interrogation unit may successively identify the presence of the
MEMS sensor strips 1910, and the position of the plug 1930 may be
determined for example by counting the number of strips 1910 passed
(e.g., where a location of one or more strips is known and/or the
distance between strips is known) and/or by employing one or more
unique identifiers with the MEMS sensors (e.g., strips 1910a, b, c,
d, and e have corresponding unique identifies A, B, C, D, and E,
and the location of a strip having a given identifier is known).
The data interrogation unit 1940 may then transmit the sensor data
to the processing unit 1920 for further processing, for example
look-up or correlation of MEMS sensor identifiers with known
locations in the wellbore. When the data interrogation unit 1940
reaches the MEMS sensor strip 1910 proximate to and/or integral
with a seat such as a float collar 1950 positioned in the casing
20, the data regarding the vertical position of the MEMS sensors
1912 in this MEMS sensor strip 1910 may be transmitted to the data
interrogation unit 1940 and the processor 1920 and give the
processor 1920 an indication that the plug 1930 has engaged/seated
(e.g., the wiper plug as landed on the float collar 1950 or is very
close to landing on the float collar 1950). In response to
receiving this data, the processor 1920 may cause pumping of the
displacement fluid to be controlled (e.g., slowed and/or
terminated).
[0214] In an embodiment, the data interrogation unit 1940 may
transmit sensor data to the processor 1920 via a data line that is
attached to the data interrogation unit 1940 and the processor 1920
and follows the data interrogation unit 1940 into the wellbore 18.
In a further embodiment, the data interrogation unit 1940 may
transmit sensor data to the processor 1920 via regional
communication boxes attached to the casing and spaced along a
length of the casing. In alternative embodiments, the data
interrogation unit may employ wireless communication, for example a
MEMS sensor network where MEMS sensors are located in a wellbore
servicing fluid proximate the plug (e.g., in a cement slurry
located in front of the plug) and/or via telemetry induced via
contact with the casing (e.g., during pumping and/or upon seating
in the float collar).
[0215] In an embodiment, the MEMS sensors 1912 in the MEMS sensor
strips 1910 may be configured to measure a concentration of a gas
in the casing 20 along the length of the casing 20 and transmit
data regarding the gas concentration to the processor 1920 via
communication boxes attached to the casing and spaced along a
length of the casing or any other communication means disclosed
herein. The gas may comprise, for example, CH.sub.4, H.sub.2S
and/or CO.sub.2. In an embodiment, from measured methane
concentrations along the length of the casing 20, the MEMS sensors
1912 may provide an indication, for example, that methane is
advancing rapidly up the casing 20, so that necessary emergency
actions may be taken, e.g., signaling for the closing of one or
more emergency or safety valves or blowout preventors.
[0216] In a further embodiment, a wellbore servicing fluid (e.g.,
cement composition) comprising a plurality of MEMS sensors may be
placed into the casing. The MEMS sensors may be suspended in and
distributed throughout the wellbore servicing fluid (e.g., cement
slurry and/or set cement forming a cement sheath). The MEMS sensors
(e.g., in strips 1910 and/or in the wellbore servicing composition)
may measure at least one wellbore parameter and transmit data
regarding the wellbore parameter to the processor 1920 via a
network consisting of the MEMS sensors in the wellbore servicing
fluid and/or the MEMS sensors 1912 situated in the MEMS sensor
strips 1910.
[0217] Referring to FIG. 28b, a method 1960 of servicing a wellbore
is described. At block 1962, a plurality of
Micro-Electro-Mechanical System (MEMS) sensors is optionally placed
in a wellbore servicing fluid, e.g., a cement composition. At block
1964, the wellbore servicing fluid is placed in the wellbore. In
addition to or in lieu of MEMS sensors in the wellbore servicing
fluid, the wellbore further comprises MEMS sensors disposed in one
or more composite resin or composite elements. For example, the
composite resin elements may be molded to an inner wall of a casing
situated in the wellbore and spaced along a length of the casing.
At block 1966, a network consisting of the MEMS sensors in the
wellbore is formed (e.g., network of MEMS sensors in the wellbore
servicing fluid and/or contained within one or more resin or
composite elements. At block 1968, data obtained by the MEMS
sensors in the wellbore is transmitted from an interior of the
wellbore to an exterior of the wellbore via the network. In
embodiments, the data may be obtained from the MEMS sensors via one
or more data interrogators present in a wellbore servicing tool run
into the wellbore prior to, concurrent with, and/or subsequent to
the wellbore servicing operation. In an embodiment, the one or more
data interrogation units is integral with a wiper plug pumped
behind a cement slurry.
[0218] In an embodiment, a cement composition is pumped into a
wellbore, followed by a wiper plug having a data interrogation unit
integral therewith, and a float collar having MEMS sensors integral
therewith is located at a terminal end of the casing, wherein
engagement of the wiper plug with the float collar is signaled from
downhole to the surface (e.g., via various communication
means/networks as described herein) by the MEMS sensors interacting
with the interrogation unit such that pumping of the cement
composition may be controlled in response to the position of the
wiper plug conveyed from downhole to the surface.
[0219] FIG. 29a is a schematic view of an embodiment of a wellbore
parameter sensing system 2000, which comprises the wellbore 18, the
casing 20 situated in the wellbore 18, a processing unit 2010
situated at an exterior of the wellbore 18 and a plurality of MEMS
sensor strips 2020 attached to the casing 20 and spaced along a
length of the casing 20. In an embodiment, the MEMS sensor strips
2020 comprise a composite resin material, in which MEMS sensors
2022 are mixed and distributed, and which may be molded to the
casing 20. As shown in FIG. 29a, the sensor strips 2022 may be
located on an exterior wall or surface of the casing 20 (e.g., a
side facing or adjacent the wellbore wall). The sensor strips 2022
may be disposed with in the casing wall (e.g., outer surface) in
accordance with sensor strips 1910 of FIG. 28a, which are shown by
way of non-limiting example on an interior surface or wall of
casing 20. In an embodiment, the MEMS sensor strips 2020 may be
embedded in grooves 2024 in the outer wall of the casing 20 so as
not to protrude from the outer wall of the casing 20. In an
embodiment, the MEMS sensor strips 2020 may be mounted flush with
the outer wall of the casing 20. In a further embodiment, the MEMS
sensor strips 2020 may be attached to casing collars. In an
embodiment, a wellbore servicing fluid, e.g., a cement slurry
comprising MEMS sensors 2032 mixed and distributed in the cement
slurry, may be placed into the annulus 26 and, in the case of the
cement slurry, allowed to cure to form a cement sheath 2030.
[0220] The MEMS sensors 2022 and/or 2032 may be active sensors,
e.g., powered by batteries situated in the MEMS sensors. The
batteries in the MEMS sensors may be inductively rechargeable by a
recharging unit lowered into the casing 20 via a wireline. In
embodiments, the MEMS sensors are powered and/or
queried/interrogated by one or more interrogation units in the
wellbore (fixed units and/or mobile units) as described in various
embodiments herein. In addition, the MEMS sensors 2022 and/or 2032
may be configured to measure at least one wellbore parameter, e.g.,
a concentration of a gas such as CH.sub.4, H.sub.2S or CO.sub.2 in
the annulus 26. Such gas detecting capability may be further used
to monitor a cement composition placed in the annulus, for example
monitoring for gas inflow/channeling while the slurry is being
placed and/or monitoring for the presence of annular gas over the
life of the wellbore (which may indicate cracks, delamination, etc.
of the cement sheath thus requiring remedial servicing). In an
embodiment, from measured methane concentrations in the annulus 26
along a length of the casing 20, the MEMS sensors 2022 and/or 2032
may provide an indication, for example, that methane is advancing
rapidly up the annulus 26, so that necessary emergency actions may
be taken.
[0221] In operation, in an embodiment, the MEMS sensors 2032 in the
cement sheath 2030 and/or the MEMS sensors in strips 2020 may
measure the at least one wellbore parameter and transmit data
regarding the at least one wellbore parameter up the annulus 26 to
the processing unit 2010 via a network consisting of the MEMS
sensors 2032 and/or the MEMS sensors 2022. For example, the MEMS
sensors may be powered up and/or interrogated by a mobile
interrogation unit run into the wellbore, for example via a plug
pumped into the wellbore (e.g., a wiper plug) and/or an
interrogation tool deployed by wireline or coiled tubing. Double
arrows 2040 indicate transmission of sensor data between
neighboring MEMS sensors 2032, arrows 2042, 2044 indicate
transmission of sensor data up the annulus 26 from MEMS sensors
2032 to MEMS sensors 2022, and arrows 2046, 2048 indicate
transmission of sensor data up the annulus 26 from MEMS sensors
2022 to MEMS sensors 2032.
[0222] Referring to FIG. 29b, a method 2060 of servicing a wellbore
is described. At block 2062, a plurality of
Micro-Electro-Mechanical System (MEMS) sensors is placed in a
wellbore servicing fluid and/or within one or more resin/composite
elements disposed in the wellbore. At block 2064, the wellbore
servicing fluid is placed in the wellbore. At block 2066, a network
consisting of the MEMS sensors in the wellbore servicing fluid
and/or MEMS sensors situated in composite resin elements is formed.
In an embodiment, the composite resin elements are molded to an
inner and/or outer wall of a casing situated in the wellbore and
spaced along a length of the casing. At block 2068, data is
obtained from the MEMS sensors in the wellbore servicing fluid
and/or resin/composite elements via one or more data interrogation
units in the wellbore and is transmitted from an interior of the
wellbore to an exterior of the wellbore via the network. In an
alternative embodiment, MEMS sensor data is collected and stored by
a mobile data interrogation unit that traverses the wellbore and is
retrieved to the surface, which may be used in addition to or in
lieu of the MEMS sensor network to transmit sensor data to the
surface.
[0223] FIG. 30a is a schematic view of an embodiment of a wellbore
parameter sensing system 2100, which comprises the wellbore 18, the
casing 20 situated in the wellbore 18, a plurality of centralizers
2110 situated between the casing 20 and the wellbore 18 and spaced
along a length of the casing 20, and a processing unit 2120
situated at an exterior of the wellbore 18. In an embodiment, the
centralizers are bow-spring type centralizers comprising a
plurality of bows extending between upper and lower collars. In an
embodiment, the centralizers 2110 may comprise MEMS sensor strips
2130, which for example are attached to at least one component
(e.g., collar 2112) of each centralizer 2110. The MEMS sensor
strips 2130 may comprise a composite resin material, in which MEMS
sensors 2132 are mixed and distributed, and which may be molded to
and/or integral with the collars 2112. In an embodiment, the MEMS
sensor strips 2130 may be embedded in channels or grooves 2134 in
the collars 2112 so as not to protrude from the collars 2112. In an
embodiment, the MEMS sensor strips 2130 may be mounted flush with
the collars 2112. In an embodiment, a wellbore servicing fluid,
e.g., a cement slurry comprising MEMS sensors 2142 mixed and
distributed in the cement slurry, may be placed into the annulus 26
and, in the case of the cement slurry, allowed to cure to form a
cement sheath 2140. While FIG. 30a shows the use of a centralizer
in conjunction with casing, it should be understood that
centralizers containing MEMS and/or data interrogation units as
described herein may be used to position any type of downhole tool
or servicing string (e.g., production tubing, etc.), and may be
used in cased and/or uncased wellbores.
[0224] In an embodiment, the MEMS sensors 2132 may be active
sensors, e.g., powered by batteries situated in the MEMS sensors
2132. The batteries in the MEMS sensors 2132 may be inductively
rechargeable by a recharging unit lowered into the casing 20 via a
wireline. In embodiments, the MEMS sensors are powered and/or
queried/interrogated by one or more interrogation units in the
wellbore (fixed units and/or mobile units) as described in various
embodiments herein. The MEMS sensors 2142 situated in the cement
slurry 2140 and/or the MEMS sensors 2132 in the centralizers may be
configured to measure at least one wellbore parameter, e.g., a
stress or strain and/or a moisture content and/or a CH.sub.4,
H.sub.2S or CO.sub.2 concentration and/or a concentration and/or a
temperature. In an embodiment, the MEMS sensors 2132 and/or 2142
may be configured to measure a concentration of a gas such as
CH.sub.4, H.sub.2S or CO.sub.2 in the annulus 26. Such gas
detecting capability may be further used to monitor a cement
composition placed in the annulus, for example monitoring for gas
inflow/channeling while the slurry is being placed and/or
monitoring for the presence of annular gas over the life of the
wellbore (which may indicate cracks, delamination, etc. of the
cement sheath thus requiring remedial servicing). In an embodiment,
from measured methane concentrations in the annulus 26 along a
length of the casing 20, the MEMS sensors 2132 and/or 2142 may
provide an indication, for example, that methane is advancing
rapidly up the annulus 26, so that necessary emergency actions may
be taken.
[0225] In operation, in an embodiment, the MEMS sensors 2142 in the
cement sheath 2140 and/or the MEMS sensors 2132 in the centralizers
may measure the at least one wellbore parameter and transmit data
regarding the at least one wellbore parameter up the annulus 26 to
the processing unit 2120 via a network consisting of the MEMS
sensors 2142 and/or the MEMS sensors 2132. For example, the MEMS
sensors may be powered up and/or interrogated by a mobile
interrogation unit run into the wellbore, for example via a plug
pumped into the wellbore (e.g., a wiper plug) and/or an
interrogation tool deployed by wireline or coiled tubing. Double
arrows 2150 indicate transmission of sensor data between
neighboring MEMS sensors 2142, arrows 2152, 2154 indicate
transmission of sensor data up the annulus 26 from MEMS sensors
2142 to MEMS sensors 2132, and arrows 2156, 2158 indicate
transmission of sensor data up the annulus 26 from MEMS sensors
2132 to MEMS sensors 2142.
[0226] Referring to FIG. 30b, a method 2170 of servicing a wellbore
is described. At block 2172, a plurality of
Micro-Electro-Mechanical System (MEMS) sensors is placed in a
wellbore servicing fluid and/or within one or more centralizers
disposed in the wellbore. At block 2174, the wellbore servicing
fluid is placed in the wellbore. At block 2176, a network
consisting of the MEMS sensors in the wellbore servicing fluid
and/or MEMS sensors situated in one or more centralizers is formed.
For example, one or more composite resin elements are molded to or
otherwise formed integral with (e.g., molded with) a plurality of
centralizers disposed between a wall of the wellbore and a casing
situated in the wellbore. The centralizers are spaced along a
length of the casing. At block 2178, data obtained from the MEMS
sensors in the wellbore servicing fluid and/or in the centralizers
via one or more data interrogation units in the wellbore and is
transmitted from an interior of the wellbore to an exterior of the
wellbore via the network. In an alternative embodiment, MEMS sensor
data is collected and stored by a mobile data interrogation unit
that traverses the wellbore and is retrieved to the surface, which
may be used in addition to or in lieu of the MEMS sensor network to
transmit sensor data to the surface.
[0227] FIG. 31 is a schematic view of an embodiment of a wellbore
parameter sensing system 2200, which comprises the wellbore 18, the
casing 20 situated in the wellbore 18, a plurality of centralizers
2210 situated between the casing 20 and the wellbore 18 and spaced
along a length of the casing 20, and a processing unit 2220. In an
embodiment, the centralizers 2210 may comprise data interrogation
units 2230, which for example are attached to at least one
component (e.g., collar 2212) of each centralizer 2210. In an
embodiment, the data interrogation units 2230 may be molded to the
collars 2212, using a composite resin material 2232. The data
interrogation units 2230 may be embedded in channels or grooves
2234 in the collars 2212 so as to not protrude from the collars
2212. In an embodiment, the data interrogation units 2230 may be
mounted flush with the collars 2212. In an embodiment, a wellbore
servicing fluid, e.g., a cement slurry comprising MEMS sensors 2242
mixed and distributed in the cement slurry, may be placed into the
annulus 26 and, in the case of the cement slurry, allowed to cure
to form a cement sheath 2240. In an embodiment, data interrogation
units 2230 are used to capture MEMS sensor data for use in fluid
flow dynamic analysis as described herein (e.g., measuring
turbulence of flow around/through the centralizers 2210).
[0228] In an embodiment, the data interrogation units 2230 may be
powered by an electrical line that may run along an outer wall of
the casing 20 and couples each data interrogation unit 2230 with a
power supply at an exterior of the wellbore 18. In an alternative
embodiment, the electrical line may run inside a longitudinal
groove in the casing 20. In a further embodiment, the data
interrogation units 2230 may be powered by batteries. The batteries
may be inductively rechargeable via a recharging unit that is
lowered down the casing 20 on a wire line. In other embodiments,
the data interrogation units 2230 may be powered by one or more
downhole power sources (e.g., fluid flow, heat, etc.).
[0229] In an embodiment, the data interrogation units 2230 may
wirelessly communicate with each other and with the processing unit
2220. In an alternative embodiment, the data interrogation units
2230 may communicate with each other and with the processing unit
2220 via a data line that may run along the casing 20, outside of
the casing 20, and couples each data interrogation unit 2230 with
the processing unit 2220. In a further embodiment, the data
interrogation units 2230 may communicate with each other and with
the processing unit 2220 via a data line that runs inside a groove
in the casing and couples the data interrogation units 2230 with
each other and the processing unit 2220. The data interrogation
units may further communicate with each other via various networks
disclosed herein, for example a network of MEMS sensors 2242, a
network of data interrogation units 2230, and/or via one or more
regional data interrogation units/or communication hubs such as
unit 2141 (which may communicate wirelessly downhole and via wire
to the surface). In embodiments, the data interrogation units 2230
may operate (e.g., gather and/or communicate data) via one or more
means or modes as described with respect to FIGS. 5-16.
[0230] In an embodiment, the MEMS sensors 2242 may be active
sensors, e.g., powered by batteries situated in the MEMS sensors
2242. The batteries in the MEMS sensors 2242 may be inductively
rechargeable by a recharging unit lowered into the casing 20 via a
wireline. In embodiments, the MEMS sensors are powered and/or
queried/interrogated by one or more interrogation units in the
wellbore (fixed units 2230 and/or mobile units) as described in
various embodiments herein. The MEMS sensors 2242 situated in the
cement slurry 2240 may be configured to measure at least one
wellbore parameter, e.g., a stress or strain and/or a moisture
content and/or a CH.sub.4, H.sub.2S or CO.sub.2 concentration
and/or a concentration and/or a temperature. In an embodiment, the
MEMS sensors 2240 may be configured to measure a concentration of a
gas such as CH.sub.4, H.sub.2S or CO.sub.2 in the annulus 26. Such
gas detecting capability may be further used to monitor a cement
composition placed in the annulus, for example monitoring for gas
inflow/channeling while the slurry is being placed and/or
monitoring for the presence of annular gas over the life of the
wellbore (which may indicate cracks, delamination, etc. of the
cement sheath thus requiring remedial servicing). In an embodiment,
from measured methane concentrations in the annulus 26 along a
length of the casing 20, the MEMS sensors 2240 may provide an
indication, for example, that methane is advancing rapidly up the
annulus 26, so that necessary emergency actions may be taken.
[0231] In operation, in an embodiment, the MEMS sensors 2242 in the
cement sheath 2240 may measure the at least one wellbore parameter
and transmit data regarding the at least one wellbore parameter
directly and/or indirectly (e.g., via one or more adjacent MEMS
sensors, e.g., daisy-chain) to data interrogation units 2230
situated in a vicinity of the MEMS sensors 2242. The data
interrogation units 2230 may then transmit the sensor data
wirelessly and/or via wire to the surface. In an embodiment the
data interrogation units 2230 transmit the sensor data to
neighboring data interrogation units 2230 (e.g., daisy-chain) and
up the wellbore 18 to the processing unit and/or or transmit the
sensor data through the data line, up the wellbore 18 and to the
processing unit 2220. The processing unit may then process the
sensor data. Double arrows 2250 indicate transmission of sensor
data between neighboring MEMS sensors 2242; arrows 2254, 2256
indicate transmission of sensor data uphole from MEMS sensors 2242
to closest data interrogation units 2230; arrows 2260, 2262
indicate transmission of sensor data downhole from MEMS sensors
2242 to closest data interrogation units 2230; and arrows 2252,
2258 represent the transmission of data up and down the wellbore,
for example via a network of interrogation units 2230 and/or MEMS
sensors 2242.
[0232] In an embodiment, MEMS sensors and/or one or more data
interrogation units may be molded into a casing shoe, e.g., a guide
shoe or a float shoe, and used to measure at least one parameter of
a wellbore in which the casing shoe is situated. The casing shoe
may be made of a homogeneous material, for example, a plastic such
as a thermoplastic material or a thermoset material. In addition,
the casing shoe may be formed by injection molding, thermal
casting, thermal molding, extrusion molding, or any combination of
these methods. Examples of thermoplastic and thermoset materials
suitable for forming the casing shoe may be found in U.S. Pat. No.
7,617,879, which is hereby incorporated by reference herein in its
entirety.
[0233] In an embodiment, the MEMS sensors and/or data interrogation
units may be molded into the thermoplastic or thermoset material of
the casing shoe such that at least a portion of the MEMS sensors
are situated at or immediately proximate to an outer surface of the
casing shoe and are able to measure a parameter of the wellbore,
e.g., a stress or strain and/or a moisture content and/or a
CH.sub.4, H.sub.2S or CO.sub.2 concentration and/or a concentration
and/or a temperature.
[0234] It should be noted that any of the embodiments of FIGS.
27-31 may be combined with embodiments where MEMS sensors are
contained in one or more wellbore servicing fluids or compositions,
for example the embodiments of FIGS. 5-26. Where MEMS sensors are
employed in at least one wellbore servicing fluid or composition in
combination with MEMS sensors combined into one or more wellbore
servicing equipment or tools, the MEMS sensors may be the same or
different (e.g., Type "A", "B", etc.), and such combinations of
same and/or different sensor may be used to provide different or
distinct signals to the data interrogators, for example as
described in relation to the embodiments of FIGS. 22-24, and such
different or distinct signals may further facilitate action (e.g.,
changing, controlling, receiving, monitoring, etc.) with respect to
one or more operational parameters or conditions of the downhole
equipment and/or servicing operation.
[0235] In embodiments, one or more acoustic sensors may be used in
combination with MEMS sensors and/or data interrogation units
placed in the wellbore. For example, one or more acoustic sensors
may be incorporated into data interrogation and communication units
for MEMS sensors, in order to measure further wellbore parameters
and/or provide further options for transmitting sensor data from an
interior of a wellbore to an exterior of the wellbore.
[0236] FIG. 32 illustrates an embodiment of a portion of a wellbore
parameter sensing system 2300. The wellbore parameter sensing
system 2300 comprises the wellbore 18, the casing 20 situated in
the wellbore 18, a plurality of interrogation/communication units
2310 attached to the casing 20 and spaced along a length of the
casing 20, a processing unit 2320 situated at an exterior of the
wellbore and communicatively linked to the units 2310, and a
wellbore servicing fluid 2330 situated in the wellbore 18. The
wellbore servicing fluid 2330 may comprise a plurality of MEMS
sensors 2340, which are configured to measure at least one wellbore
parameter. In an embodiment, FIG. 32 represents an
interrogation/communication unit 2310 located on an exterior of the
casing 20 in annular space 26 and surrounded by a cement
composition comprising MEMS sensors. The unit 2310 may further
comprise a power source, for example a battery (e.g., lithium
battery) or power generator. In embodiments, the components of unit
2310 are powered by any of the embodiments of FIGS. 33, 34, and 35
described herein.
[0237] In an embodiment, the unit 2310 may comprise an
interrogation unit 2350, which is configured to interrogate the
MEMS sensors 2340 and receive data regarding the at least one
wellbore parameter from the MEMS sensors 2340. In an embodiment,
the unit 2310 may also comprise at least one acoustic sensor 2352,
which is configured to input ultrasonic waves 2354 into the
wellbore servicing fluid 2330 and/or into the oil or gas formation
14 proximate to the wellbore 18 and receive ultrasonic waves
reflected by the wellbore servicing fluid 2330 and/or the oil or
gas formation 14. In an embodiment, the at least one acoustic
sensor 2352 may transmit and receive ultrasonic waves using a
pulse-echo method or pitch-catch method of ultrasonic
sampling/testing. A discussion of the pulse-echo and pitch-catch
methods of ultrasonic sampling/testing may be found in the NASA
preferred reliability practice no. PT-TE-1422, "Ultrasonic Testing
of Aerospace Materials," which is incorporated by reference herein
in its entirety. In alternative embodiments, ultrasonic waves
and/or acoustic sensors may be provided via the unit 2310 in
accordance with one or more embodiments disclosed in U.S. Pat. Nos.
5,995,477; 6,041,861; or 6,712,138, each of which is incorporated
herein in its entirety.
[0238] In an embodiment, the at least one acoustic sensor 2352 may
be able to detect a presence and a position in the wellbore 18 of a
liquid phase and/or a solid phase of the wellbore servicing fluid
2330. In addition, the at least one acoustic sensor 2352 may be
able to detect a presence of cracks and/or voids and/or inclusions
in a solid phase of the wellbore servicing fluid 2330, e.g., in a
partially cured cement slurry or a fully cured cement sheath. In a
further embodiment, the acoustic sensor 2352 may be able to
determine a porosity of the oil or gas formation 14. In a further
embodiment, the acoustic sensor 2352 may be configured to detect a
presence of the MEMS sensors 2340 in the wellbore servicing fluid
2330. In particular, the acoustic sensor may scan for the physical
presence of MEMS sensors proximate thereto, and may thereby be used
to verify data derived from the MEMS sensors. For example, where
acoustic sensor 2352 does not detect the presence of MEMS sensors,
such lack of detection may provide a further indication that a
wellbore servicing fluid has not yet arrived at that location (for
example, has not entered the annulus). Likewise, where acoustic
sensor 2352 does detect the presence of MEMS sensors, such presence
may be further verified by interrogation on the MEMS sensors.
Furthermore, a failed attempt to interrogate the MEMS sensors where
acoustic sensor 2352 indicates their presence may be used to
trouble-shoot or otherwise indicate that a problem may exist with
the MEMS sensor system (e.g., a fix data interrogation unit may be
faulty thereby requiring repair and/or deployment of a mobile unit
into the wellbore). In various embodiments, the acoustic sensor
2352 may perform any combination of the listed functions.
[0239] In an embodiment, the acoustic sensor 2352 may be a
piezoelectric-type sensor comprising at least one piezoelectric
transducer for inputting ultrasonic waves into the wellbore
servicing fluid 2330. A discussion of acoustic sensors comprising
piezoelectric composite transducers may be found in U.S. Pat. No.
7,036,363, which is hereby incorporated by reference herein in its
entirety.
[0240] In an embodiment, the interrogation/communication unit 2310
may further comprise an acoustic transceiver 2356. The acoustic
transceiver 2356 may comprise an acoustic receiver 2358, an
acoustic transmitter 2360 and a microprocessor 2362. The
microprocessor 2362 may be configured to receive MEMS sensor data
from the interrogation unit 2350 and/or acoustic sensor data from
the at least one acoustic sensor 2352 and convert the sensor data
into a form that may be transmitted by the acoustic transmitter
2360.
[0241] In an embodiment, the acoustic transmitter 2360 may be
configured to transmit the sensor data from the MEMS sensors 2340
and/or the acoustic sensor 2352 to an interrogation/communication
unit situated uphole (e.g., the next unit directly uphole) from the
unit 2310 shown in FIG. 32. The acoustic transmitter 2360 may
comprise a plurality of piezoelectric plate elements in one or more
plate assemblies configured to input ultrasonic waves into the
casing 20 and/or the wellbore servicing fluid 2330 in the form of
acoustic signals (for example to provide acoustic telemetry
communications/signals as described in various embodiments herein).
Examples of acoustic transmitters comprising piezoelectric plate
elements are given in U.S. Patent Application Publication No.
2009/0022011, which is hereby incorporated by reference herein in
its entirety.
[0242] In an embodiment, the acoustic receiver 2358 may be
configured to receive sensor data in the form of acoustic signals
from one or more acoustic transmitters disposed in one or more
interrogation/communication units situated uphole and/or downhole
from the unit 2310 shown in FIG. 32. In addition, the acoustic
receiver 2358 may be configured to transmit the sensor data to the
microprocessor 2362. In embodiments, a microprocessor or digital
signal processor may be used to process sensor data, interrogate
sensors and/or interrogation/communication units and communicate
with devices situated at an exterior of a wellbore. For example,
the microprocessor 2362 may then route/convey/retransmit the
received data (and additionally/optionally convert or process the
received data) to the interrogation/communication unit situated
directly uphole and/or downhole from the unit 2310 shown in FIG.
32. Alternatively, the received sensor data may be passed along to
the next interrogation/communication unit without undergoing any
transformation or further processing by microprocessor 2362. In
this manner, sensor data acquired by interrogators 2350 and
acoustic sensors 2352 situated in units 2310 disposed along at
least a portion of the length of the casing 20 may be transmitted
up or down the wellbore 18 to the processing unit 2320, which is
configured to process the sensor data.
[0243] In embodiments, sensors, processing electronics,
communication devices and power sources, e.g., a lithium battery,
may be integrated inside a housing (e.g., a composite attachment or
housing) that may, for example, be attached to an outer surface of
a casing. In an embodiment, the housing may comprise a composite
resin material. In embodiments, the composite resin material may
comprise an epoxy resin. In further embodiments, the composite
resin material may comprise at least one ceramic material. In
further embodiments, housing of unit 2310 (e.g., composite housing)
may extend from the casing and thereby serving additional functions
such as a centralizer for the casing. In alternative embodiments,
the housing of unit 2310 (e.g., composite housing) may be contained
within a recess in the casing and by mounted flush with a wall of
the casing. Alternative configurations and locations for the unit
2310 (e.g., a composite housing) are shown in FIGS. 33-35 as
described herein. Any of the composite materials described herein
may be used in embodiments to form a housing for unit 2310.
[0244] In embodiments, sensors (e.g., the acoustic sensors 2352
and/or the MEMS sensors 2340) may measure parameters of a wellbore
servicing material in an annulus situated between a casing and an
oil or gas formation. The wellbore servicing material may comprise
a fluid, a cement slurry, a partially cured cement slurry, a cement
sheath, or other materials. Parameters of the wellbore and/or
servicing material may be acquired and transmitted continuously or
in discrete time, depending on demands. In embodiments, parameters
measured by the sensors include velocity of ultrasonic waves,
Poisson's ratio, material phases, temperature, flow, compactness,
pressure and other parameters described herein. In embodiments, the
unit 2310 may contain a plurality of sensor types used for
measuring the parameters, and may include lead zirconate titanate
(PZT) acoustic transceivers, electromagnetic transceivers, pressure
sensors, temperature sensors and other sensors.
[0245] In embodiments, unit 2310 may be used, for example, to
monitor parameters during a curing process of cement situated in
the annulus. In further embodiments, flow of production fluid
through production tubing and/or the casing may be monitored. In
embodiments an interrogation/communication unit (e.g., unit 2310)
may be utilized for collecting data from sensors, processing data,
storing information, and/or sending and receiving data. Different
types of sensors, including electromagnetic and acoustic sensors as
well as MEMS sensors, may be utilized for measuring various
properties of a material and determining and/or confirming an
actual state of the material. In an embodiment, data to be
processed in the interrogation/communication unit may include data
from acoustic sensors, e.g., liquid/solid phase, annulus width,
homogeneity/heterogeneity of a medium, velocity of acoustic waves
through a medium and impedance, as well as data from MEMS sensors,
which in embodiments include passive RFID tags and are interrogated
electromagnetically. In an embodiment, each
interrogation/communication unit may process data pertaining to a
vicinity or region of the wellbore associated to the unit.
[0246] In a further embodiment, the interrogation/communication
unit may further comprise a memory device configured to store data
acquired from sensors. The sensor data may be tagged with time of
acquisition, sensor type and/or identification information
pertaining to the interrogation/communication unit where the data
is collected. In an embodiment, raw and/or processed sensor data
may be sent to an exterior of a wellbore for further processing or
analysis, for example via any of the communication means, methods,
or networks disclosed herein.
[0247] In an embodiment, data acquired by the
interrogation/communication units may be transmitted acoustically
from unit to unit and to an exterior of the wellbore, using the
casing as an acoustic transmission medium. In a further embodiment,
sensor data from each interrogation/communication unit may be
transmitted to an exterior of the wellbore, using a very low
frequency electromagnetic wave. Alternatively, sensor data from
each interrogation/communication unit may be transmitted via a
daisy-chain to an exterior of the wellbore, using a very low
frequency electromagnetic wave to pass the data along the chain. In
a further embodiment, a wire and/or fiber optic line coupled to
each of the interrogation/communication units may be used to
transmit sensor data from each unit to an exterior of the wellbore,
and also used to power the units.
[0248] In an embodiment, a circumferential acoustic scanning tool
comprising an acoustic transceiver may be lowered into a casing,
along which the interrogation/communication units are spaced. The
acoustic transceiver in the circumferential acoustic scanning tool
may be configured to interrogate corresponding acoustic
transceivers in the interrogation/communication units, by
transmitting an acoustic signal through the casing to the acoustic
transceiver in the unit. In an embodiment, the memory devices in
each interrogation/communication unit may be able to store, for
example, two weeks worth of sensor data before being interrogated
by the circumferential acoustic scanning tool. The acoustic
transceiver in the circumferential acoustic scanning tool may
further comprise a MEMS sensor interrogation unit, and thereby
interrogate and collect data from MEMS sensors.
[0249] In embodiments, data interrogation/communication units or
tools of the various embodiments disclosed herein may be powered by
devices configured to generate electricity while the units are
located in the wellbore, for example turbo generator units and/or
quantum thermoelectric generator units. The electricity generated
by the devices may be used directly by components in the
interrogation/communication units or may be stored in a battery or
batteries for later use.
[0250] FIG. 33 illustrates an embodiment of a turbo generator unit
2370 situated in a side compartment 2380 (e.g., side pocket
mandrel) of the casing 20. The turbo generator unit 2370 may
comprise a generator 2390 driven by a turbine 2400. The turbo
generator unit 2370 may also comprise a battery 2410 for storing
electricity generated by the generator 2390.
[0251] In an embodiment, a portion of a wellbore servicing fluid
2420 flowing through casing 20 in the direction of arrows 2430 may
be diverted in a direction of arrows 2432, into a flow channel 2440
of side compartment 2380, and past turbine 2400. A force of the
wellbore servicing fluid 2420 flowing past turbine 2400 causes the
turbine 2400 to rotate and drive the generator 2390. In an
embodiment, electricity generated by the generator 2390 may power
components in one or more interrogation/communication units
directly and/or may be stored in battery 2410 for later use by
components in one or more interrogation/communication units. In a
further embodiment, the turbo generator unit 2370 may also comprise
a controller for regulating current flow into the battery 2410
and/or current flow into components of the
interrogation/communication units. In an embodiment, the turbo
generator unit 2370 is proximate to and/or integral with a unit
powered thereby.
[0252] FIG. 34 illustrates a further embodiment of the turbo
generator unit 2370 shown in FIG. 33. In this embodiment, the turbo
generator unit 2370 is situated in the annulus 26 between the
wellbore 18 and the casing 20. In addition, the turbo generator
unit 2370 is oriented in the annulus 26 such that a wellbore
servicing fluid 2450 pumped down an interior of the casing 20 in
the direction of arrows 2460 and up the annulus 26 in the direction
of arrows 2462 forces the turbine 2400 to rotate and drive
generator 2390. As in the embodiment illustrated in FIG. 33,
electricity generated by generator 2390 may be stored in battery
2410 or used directly by components situated in an
interrogation/communication unit. In addition to or in lieu of the
flow of a wellbore servicing fluid as driving the turbo generator
unit 2370, a flow of fluid from the formation and/or up the
wellbore (e.g., the recovery of hydrocarbons from the well) may
provide the fluid flow that powers the turbo generator unit.
[0253] In further embodiments, the turbo generator unit 2370 may be
oriented in the interior of the casing 20 or in the annulus 26 such
that a wellbore servicing fluid flowing in a downhole direction can
drive the generator 2390. In other embodiments, the turbo generator
unit 2370 may be attached to production tubing instead of the
casing 20, and the production of formation fluids may power the
turbo generator. An example of a generator attached to production
tubing is described in U.S. Pat. No. 5,839,508, which is hereby
incorporated by reference herein in its entirety.
[0254] In embodiments, thermoelectricity, which may be generally
defined as the conversion of temperature differences to
electricity, may be used for generating electricity in a wellbore
via a thermoelectric generator. In one example of
thermoelectricity, electrons in a first material that is at a
higher temperature than a second material may quantum-mechanically
tunnel from the first material to the second material when a
distance between the two materials is sufficiently small. The
quantum-mechanical tunneling of the electrons may generate a
current that may be used to power downhole devices, e.g.,
interrogation/communication units and/or MEMS sensors. Examples of
utilizing thermoelectricity for powering downhole devices may be
found in U.S. Pat. No. 7,647,979, which is hereby incorporated by
reference herein in its entirety.
[0255] FIG. 35 illustrates an embodiment of a quantum
thermoelectric generator 2470, which is disposed in the casing 20
situated in wellbore 18 and is electrically coupled to the
interrogation/communication unit 2310. The quantum electric
generator 2470 may comprise an emitter electrode 2472, a collector
electrode 2474 and leads 2476, 2478 that couple electrodes 2472,
2474 to the unit 2310.
[0256] In an embodiment, the wellbore servicing fluid 2330 situated
in annulus 26 may comprise a cement slurry, which has been pumped
down an interior of the casing 20 and up the annulus 26 and is
allowed to cure to form a cement sheath. As the cement cures,
exothermic hydration reactions may raise the temperature of the
curing slurry, thereby heating an outer wall 20a of the casing 20
and creating a temperature gradient in the casing between the outer
wall 20a and an inner wall 20b of the casing 20. In an embodiment,
the inner wall 20b may be in contact with a displacement fluid,
which may have a conductivity and a heat capacity sufficient to
maintain the temperature gradient. In an embodiment, in response to
a difference in temperature between the emitter electrode 2472 and
the collector electrode 2474, electrons 2480 may flow from the
emitter electrode 2472 to the collector electrode 2474, thereby
generating a current that flows through leads 2476, 2478. In an
embodiment, the current generated by quantum thermoelectric
generator 2470 may be used to power components in the
interrogation/communication unit 2310 and may be fed to the
components directly or stored in a battery.
[0257] In embodiments, the quantum thermoelectric generator 2470
may be situated in production tubing instead of the casing 20. In
other embodiments, heat from other wellbore servicing fluids such
as drilling mud may be used to generate a current in the quantum
thermoelectric generator 2470. In further embodiments, heat from
the oil or gas formation 14 adjacent to the wellbore 18, e.g., from
fluids such as hydrocarbons recovered from the formation, may be
used to generate a current in the quantum thermoelectric generator
2470.
[0258] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore servicing fluid, pumping the wellbore
servicing fluid down the wellbore at a fluid flow rate, determining
positions of the MEMS sensors in the wellbore, determining
velocities of the MEMS sensors along a length of the wellbore, and
determining an approximate cross-sectional area profile of the
wellbore along the length of the wellbore from at least the
velocities of the MEMS sensors and the fluid flow rate. In an
embodiment, a constriction in the wellbore is determined in a
volumetric region of the wellbore in which average velocities of
the MEMS sensors exceed a threshold average velocity determined
using the fluid flow rate of the wellbore servicing fluid. In an
embodiment, the average velocities of the MEMS sensors fall below
the threshold average velocity after the MEMS sensors traverse the
constriction. In an embodiment, a washout in the wellbore is
determined in a volumetric region of the wellbore in which average
velocities of the MEMS sensors fall below a threshold average
velocity determined using the fluid flow rate of the wellbore
servicing fluid. In an embodiment, the average velocities of the
MEMS sensors exceed the threshold average velocity after the MEMS
sensors traverse the washout. In an embodiment, a fluid loss zone
is determined in a volumetric region of the wellbore in which
average velocities of the MEMS sensors fall below, and remain
below, a threshold average velocity determined using the fluid flow
rate of the wellbore servicing fluid. In an embodiment, the method
further comprises determining a return fluid flow rate of the
wellbore servicing fluid up the wellbore, wherein the fluid loss
zone is additionally determined using the return fluid flow rate of
the wellbore servicing fluid. In an embodiment, the positions of
the MEMS sensors in the wellbore, the velocities of the MEMS
sensors along the length of the wellbore, and the approximate
cross-sectional area profile of the wellbore are determined at
least approximately in real time. In an embodiment, the positions
of the MEMS sensors in the wellbore are determined using a
plurality of data interrogation units spaced along the length of
the wellbore. In an embodiment, the positions of the MEMS sensors
are sensed by the MEMS sensors and are transmittable by a network
consisting of the MEMS sensors from an interior of the wellbore to
an exterior of the wellbore. In an embodiment, the MEMS sensors are
powered by a plurality of power sources spaced along the length of
the wellbore. In an embodiment, the MEMS sensors are self-powered.
In an embodiment, the MEMS sensors comprise radio frequency
identification device (RFID) tags. In an embodiment, the method
further comprises determining shapes of wellbore cross-sections
along the length of the wellbore, using positions of the MEMS
sensors detected as the MEMS sensors traverse the wellbore
cross-sections.
[0259] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore servicing fluid, placing the wellbore
servicing fluid in the wellbore, obtaining data from the MEMS
sensors using a plurality of data interrogation units spaced along
a length of the wellbore, and processing the data obtained from the
MEMS sensors. In an embodiment, the wellbore servicing fluid
comprises a drilling fluid, a spacer fluid, a sealant, a fracturing
fluid, a gravel pack fluid or a completion fluid. In an embodiment,
the MEMS sensors determine one or more parameters. In an
embodiment, the one or more parameters comprises at least one
physical parameter. In an embodiment, the one or more parameters
comprises at least one chemical parameter. In an embodiment, the at
least one physical parameter comprises at least one of a
temperature, a stress or a strain. In an embodiment, the at least
one chemical parameter comprises at least one of a CO.sub.2
concentration, an H.sub.2S concentration, a CH.sub.4 concentration,
a moisture content, a pH, an Na.sup.+ concentration, a K.sup.+
concentration and a Cl.sup.- concentration. In an embodiment, the
data interrogation units are powered via a power line running
between the data interrogation units and a power source situated at
an exterior of the wellbore. In an embodiment, the data
interrogation units are powered by at least one turbogenerator
situated in the wellbore. In an embodiment, a turbine in the
turbogenerator is driven by at least one of the wellbore servicing
fluid and a production fluid flowing through the wellbore. In an
embodiment, the data interrogation units are powered by at least
one quantum thermoelectric generator situated in the wellbore. In
an embodiment, the at least one quantum thermoelectric generator is
situated in a casing disposed in the wellbore. In an embodiment,
the at least one quantum thermoelectric generator is situated in
production tubing disposed in the wellbore. In an embodiment, the
MEMS sensors comprise radio frequency identification device (RFID)
tags. In an embodiment, the MEMS sensors are powered by the data
interrogators. In an embodiment, the MEMS sensors are self-powered.
In an embodiment, the wellbore servicing fluid is a cement slurry,
wherein the cement slurry is placed in an annulus situated between
a wall of the wellbore and an outer wall of a casing situated in
the wellbore, wherein the cement slurry is allowed to cure so as to
form a cement sheath, and wherein the MEMS sensors are configured
to measure at least one of a temperature in the cement sheath, a
gas concentration in the cement sheath, a moisture content in the
cement sheath, a pH in the cement sheath, a chloride ion
concentration in the cement sheath and a mechanical stress of the
cement sheath. In an embodiment, the MEMS sensors are configured to
measure a gas concentration in the cement slurry, wherein a degree
of gas influx into the cement slurry is determined using the gas
concentration in the cement slurry. In an embodiment, the method
further comprises determining an integrity of the cement sheath
using the data obtained from the MEMS sensors. In an embodiment,
the MEMS sensors are configured to measure a gas concentration in
the cement sheath, wherein a region of the cement sheath is
considered to be integral if the gas concentration measured by MEMS
sensors situated in an interior of the cement sheath in the region
of the cement sheath is less than a threshold value. In an
embodiment, the data interrogation units or the MEMS sensors may be
activated by a ground-penetrating signal generated by a transmitter
situated at an exterior of the wellbore.
[0260] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore servicing fluid, placing the wellbore
servicing fluid in the wellbore, forming a network comprising the
MEMS sensors, and transferring data obtained by the MEMS sensors
from an interior of the wellbore to an exterior of the wellbore via
the network. In an embodiment, the MEMS sensors are powered by a
plurality of power sources spaced along a length of the wellbore.
In an embodiment, the MEMS sensors are self-powered. In an
embodiment, the wellbore servicing fluid comprises a drilling
fluid, a spacer fluid, a sealant, a fracturing fluid, a gravel pack
fluid or a completion fluid. In an embodiment, the MEMS sensors
determine one or more parameters. In an embodiment, the one or more
parameters comprises at least one physical parameter. In an
embodiment, the one or more parameters comprises at least one
chemical parameter. In an embodiment, the at least one physical
parameter comprises at least one of a temperature, a stress or a
strain. In an embodiment, the at least one chemical parameter
comprises at least one of a CO.sub.2 concentration, an H.sub.2S
concentration, a CH.sub.4 concentration, a moisture content, a pH,
an Na.sup.+ concentration, a K.sup.+ concentration and a Cl.sup.-
concentration. In an embodiment, the MEMS sensors comprise radio
frequency identification device (RFID) tags.
[0261] Disclosed herein is a system, comprising a wellbore, a
wellbore servicing fluid situated in the wellbore, the wellbore
servicing fluid comprising a plurality of Micro-Electro-Mechanical
System (MEMS) sensors, a plurality of data interrogation units
spaced along a length of the wellbore and adapted to obtain data
from the MEMS sensors, and a processing unit adapted to receive the
data from the data interrogation units and process the data. In an
embodiment, the wellbore servicing fluid comprises a drilling
fluid, a spacer fluid, a sealant, a fracturing fluid, a gravel pack
fluid or a completion fluid. In an embodiment, the MEMS sensors are
configured to determine one or more parameters. In an embodiment,
the one or more parameters comprises at least one physical
parameter. In an embodiment, the one or more parameters comprises
at least one chemical parameter. In an embodiment, the at least one
physical parameter comprises at least one of a temperature, a
stress and a strain. In an embodiment, the at least one chemical
parameter comprises at least one of a CO.sub.2 concentration, an
H.sub.2S concentration, a CH.sub.4 concentration, a moisture
content, a pH, an Na.sup.+ concentration, a K.sup.+ concentration
and a concentration. In an embodiment, the data interrogation units
are powered via a power line running between the data interrogation
units and a power source situated at an exterior of the wellbore.
In an embodiment, the data interrogation units are powered by at
least one turbogenerator situated in the wellbore. In an
embodiment, a turbine in the turbogenerator is driven by at least
one of the wellbore servicing fluid and a production fluid flowing
through the wellbore. In an embodiment, the data interrogation
units are powered by at least one quantum thermoelectric generator
situated in the wellbore. In an embodiment, the at least one
quantum thermoelectric generator is situated in a casing disposed
in the wellbore. In an embodiment, the at least one quantum
thermoelectric generator is situated in production tubing disposed
in the wellbore. In an embodiment, the MEMS sensors comprise radio
frequency identification device (RFID) tags. In an embodiment, the
MEMS sensors are powered by the data interrogators. In an
embodiment, the MEMS sensors are self-powered. In an embodiment,
the data interrogation units or the MEMS sensors may be activated
by a ground-penetrating signal generated by a transmitter situated
at an exterior of the wellbore.
[0262] Disclosed herein is a system, comprising a wellbore, a
wellbore servicing fluid situated in the wellbore, the wellbore
servicing fluid comprising a plurality of Micro-Electro-Mechanical
System (MEMS) sensors, wherein the MEMS sensors are configured to
measure at least one parameter and transmit data associated with
the at least one parameter from an interior of the wellbore to an
exterior of the wellbore via a data transfer network consisting of
the MEMS sensors, and a processing unit adapted to receive the data
from the MEMS sensors and process the data. In an embodiment, the
wellbore servicing fluid comprises a drilling fluid, a spacer
fluid, a sealant, a fracturing fluid, a gravel pack fluid or a
completion fluid. In an embodiment, the MEMS sensors are configured
to determine one or more parameters. In an embodiment, the MEMS
sensors are powered by a plurality of power sources spaced along a
length of the wellbore. In an embodiment, the MEMS sensors comprise
radio frequency identification device (RFID) tags. In an
embodiment, the MEMS sensors are self-powered. In an embodiment,
the MEMS sensors may be activated by a ground-penetrating signal
generated by a transmitter situated at an exterior of the
wellbore.
[0263] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore servicing fluid, placing the wellbore
servicing fluid in the wellbore, obtaining data from the MEMS
sensors using a plurality of data interrogation units spaced along
a length of the wellbore, telemetrically transmitting the data from
an interior of the wellbore to an exterior of the wellbore, using a
casing situated in the wellbore, and processing the data obtained
from the MEMS sensors. In an embodiment, the wellbore servicing
fluid comprises a drilling fluid, a spacer fluid, a sealant, a
fracturing fluid, a gravel pack fluid or a completion fluid. In an
embodiment, the MEMS sensors determine one or more parameters. In
an embodiment, the one or more parameters comprises at least one
physical parameter. In an embodiment, the one or more parameters
comprises at least one chemical parameter. In an embodiment, the at
least one physical parameter comprises at least one of a
temperature, a stress or a strain. In an embodiment, the at least
one chemical parameter comprises at least one of a CO.sub.2
concentration, an H.sub.2S concentration, a CH.sub.4 concentration,
a moisture content, a pH, an Na.sup.+ concentration, a K.sup.+
concentration and a concentration. In an embodiment, the data
interrogation units are powered via a power line running between
the data interrogation units and a power source situated at the
exterior of the wellbore. In an embodiment, the data interrogation
units are powered by at least one turbogenerator situated in the
wellbore. In an embodiment, a turbine in the turbogenerator is
driven by at least one of the wellbore servicing fluid and a
production fluid flowing through the wellbore. In an embodiment,
the data interrogation units are powered by at least one quantum
thermoelectric generator situated in the wellbore. In an
embodiment, the at least one quantum thermoelectric generator is
situated in the casing. In an embodiment, the at least one quantum
thermoelectric generator is situated in production tubing disposed
in the wellbore. In an embodiment, the MEMS sensors comprise radio
frequency identification device (RFID) tags. In an embodiment, the
MEMS sensors are powered by the data interrogators. In an
embodiment, telemetrically transmitting the data from an interior
of the wellbore to an exterior of the wellbore comprises
transmitting the data on at least one insulated cable embedded in a
longitudinal groove in the casing. In an embodiment, telemetrically
transmitting the data from an interior of the wellbore to an
exterior of the wellbore comprises transmitting the data on the
casing, using the casing as an electrically conductive medium for
transmission. In an embodiment, telemetrically transmitting the
data from an interior of the wellbore to an exterior of the
wellbore comprises converting the data into acoustic vibrations of
the casing.
[0264] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, a wellbore servicing fluid
situated in the wellbore, the wellbore servicing fluid comprising a
plurality of Micro-Electro-Mechanical System (MEMS) sensors, a
plurality of data interrogation units spaced along a length of the
wellbore and adapted to obtain data from the MEMS sensors and
telemetrically transmit the data from an interior of the wellbore
to an entrance of the wellbore via the casing, and a processing
unit adapted to receive the data from the data interrogation units
and process the data. In an embodiment, the wellbore servicing
fluid comprises a drilling fluid, a spacer fluid, a sealant, a
fracturing fluid, a gravel pack fluid or a completion fluid. In an
embodiment, the MEMS sensors are configured to determine one or
more parameters. In an embodiment, the MEMS sensors comprise radio
frequency identification device (RFID) tags. In an embodiment, the
MEMS sensors are self-powered. In an embodiment, the MEMS sensors
are powered by the data interrogators. In an embodiment, the data
interrogation units or the MEMS sensors may be activated by a
ground-penetrating signal generated by a transmitter situated at an
exterior of the wellbore. In an embodiment, the casing comprises at
least one cable embedded in a groove that runs longitudinally along
at least part of a length of the casing. In an embodiment, the at
least one cable is electrically insulated from a remainder of the
casing. In an embodiment, the at least one cable comprises a
plurality of cables. In an embodiment, the data interrogation units
are electrically connected to the at least one cable. In an
embodiment, the at least one cable is configured to at least one of
a) supply power to the data interrogation units; and b) transmit
the data from the data interrogation units to the processing unit.
In an embodiment, the casing is configured to at least one of a)
supply power to the data interrogation units; and b) transmit the
data from the data interrogation units to the processing unit. In
an embodiment, the data interrogation units are powered by at least
one turbogenerator situated in the wellbore. In an embodiment, a
turbine in the turbogenerator is driven by at least one of the
wellbore servicing fluid and a production fluid flowing through the
wellbore. In an embodiment, the data interrogation units are
powered by at least one quantum thermoelectric generator situated
in the wellbore. In an embodiment, the at least one quantum
thermoelectric generator is situated in the casing. In an
embodiment, the at least one quantum thermoelectric generator is
situated in production tubing disposed in the wellbore. In an
embodiment, the system further comprises at least one acoustic
transmitter configured to transmit the data from the MEMS sensors
to the processing unit as telemetry signals in the form of acoustic
vibrations in the casing. In an embodiment, the system further
comprises an acoustic receiver configured to receive the telemetry
signals transmitted by the at least one acoustic transmitter. In an
embodiment, the system further comprises at least one repeater
configured to receive and retransmit the telemetry signals. In an
embodiment, each data interrogation unit comprises an acoustic
transmitter.
[0265] Disclosed herein is a method of servicing a wellbore,
comprising pumping a cement slurry down the wellbore, wherein a
plurality of Micro-Electro-Mechanical System (MEMS) sensors is
added to a portion of the cement slurry that is added to the
wellbore prior to a remainder of the cement slurry, and as the
cement slurry is traveling through the wellbore, determining
positions of the MEMS sensors in the wellbore along a length of the
wellbore. In an embodiment, the cement slurry is pumped down a
casing situated in the wellbore and up an annulus bounded by the
casing and the wellbore. In an embodiment, the cement slurry is
pumped down an annulus bounded by a casing situated in the wellbore
and the wellbore. In an embodiment, the positions of the MEMS
sensors in the wellbore are determined using a plurality of data
interrogation units spaced along the length of the wellbore. In an
embodiment, entry of the cement slurry into a downhole end of the
annulus is determined when at least a portion of the MEMS sensors
are detected by a data interrogation unit situated proximate to the
downhole end of the annulus. In an embodiment, the pumping is
discontinued when at least a portion of the MEMS sensors are
detected by a data interrogation unit situated proximate to an
uphole end of the annulus. In an embodiment, the pumping is
discontinued when at least a portion of the MEMS sensors are
detected by a data interrogation unit situated proximate to a
downhole end of the annulus. In an embodiment, the MEMS sensors are
powered by a plurality of power sources spaced along the length of
the wellbore. In an embodiment, the MEMS sensors are self-powered.
In an embodiment, the MEMS sensors comprise radio frequency
identification device (RFID) tags.
[0266] Disclosed herein is a method of servicing a wellbore,
comprising placing into a wellbore a first wellbore servicing fluid
comprising a plurality of Micro-Electro-Mechanical System (MEMS)
sensors having a first type of radio frequency identification
device (RFID) tag, after placing the first wellbore servicing fluid
into the wellbore, placing into the wellbore a second wellbore
servicing fluid comprising a plurality of MEMS sensors having a
second type of RFID tag, and determining positions in the wellbore
of the MEMS sensors having the first and second types of RFID tags.
In an embodiment, the method further comprises determining
volumetric regions in the wellbore occupied by the first and second
wellbore servicing fluids, using the positions in the wellbore of
the MEMS sensors having the first and second types of RFID tags. In
an embodiment, the MEMS sensors having the first type of RFID tag
are added to a portion of the first wellbore servicing fluid added
to the well bore prior to a remainder of the first wellbore
servicing fluid, and the MEMS sensors having the second type of
RFID tag are added to a portion of the second wellbore servicing
fluid added to the well bore prior to a remainder of the second
wellbore servicing fluid. In an embodiment, the method further
comprises determining an interface of the first wellbore servicing
fluid and the second wellbore servicing fluid based on the
positions in the wellbore of at least a portion of the MEMS sensors
having the second type of RFID tag. In an embodiment, the method
further comprises after placing the second wellbore servicing fluid
into the wellbore, placing into the wellbore at least one third
wellbore servicing fluid comprising a plurality of MEMS sensors
having a type of RFID tag different from the RFID tag of the MEMS
sensors of the second wellbore servicing fluid. In an embodiment,
the RFID tags of the MEMS sensors of the at least one third
wellbore servicing fluid are of the same type as the RFID tags of
the MEMS sensors of the first wellbore servicing fluid. In an
embodiment, the positions of the MEMS sensors in the wellbore are
determined using a plurality of data interrogation units spaced
along a length of the wellbore. In an embodiment, the MEMS sensors
are powered by a plurality of power sources spaced along a length
of the wellbore. In an embodiment, the MEMS sensors are
self-powered. In an embodiment, apart from the RFID tags, the first
and second wellbore servicing fluids are substantially the same
compositionally. In an embodiment, irrespective of the RFID tags,
the first and second wellbore servicing fluids are compositionally
different.
[0267] Disclosed herein is a method of servicing a wellbore,
comprising placing into a wellbore a first wellbore servicing fluid
comprising a plurality of Micro-Electro-Mechanical System (MEMS)
sensors having a first type of radio frequency identification
device (RFID) tag, after placing the first wellbore servicing fluid
into the wellbore, placing into the wellbore a second wellbore
servicing fluid comprising a plurality of MEMS sensors having the
first type of RFID tag, and determining positions in the wellbore
of the MEMS sensors having the first type of RFID tag, wherein the
MEMS sensors of the first wellbore servicing fluid are added to a
portion of the first wellbore servicing fluid added to the well
bore prior to a remainder of the first wellbore servicing fluid,
and the MEMS sensors of the second wellbore servicing fluid are
added to a portion of the second wellbore servicing fluid added to
the well bore prior to a remainder of the second wellbore servicing
fluid. In an embodiment, the portions of the first and second
wellbore servicing fluids are at least one of (a) of different
volumes and (b) of different MEMS sensor loadings. In an
embodiment, the at least one of the different volumes and the
different sensor loadings of the portions of the first and second
wellbore servicing fluids is detectable as a signal by a plurality
of data interrogation units spaced along a length of the wellbore
and transmittable from the data interrogation units to a processing
unit situated at an exterior of the wellbore. In an embodiment, the
method further comprises determining at least one of a volumetric
region of the wellbore occupied by a wellbore servicing fluid and
an interface of the wellbore servicing fluids, using the at least
one of the different volumes and the different sensor loadings of
the portions of the first and second wellbore servicing fluids. In
an embodiment, the method further comprises after placing the
second wellbore servicing fluid into the wellbore, placing into the
wellbore at least one third wellbore servicing fluid comprising a
plurality of MEMS sensors having the first type of RFID tag,
wherein the MEMS sensors of the at least one third wellbore
servicing fluid are added to a portion of the at least one third
wellbore servicing fluid added to the well bore prior to a
remainder of the at least one third wellbore servicing fluid. In an
embodiment, the first, second and at least one third wellbore
servicing fluids are substantially the same compositionally. In an
embodiment, the first, second and at least one third wellbore
servicing fluids are compositionally different. In an embodiment,
the first and at least one third wellbore servicing fluids are
substantially the same compositionally, and the second wellbore
servicing fluid comprises a spacer fluid. In an embodiment, the
first, second and at least one third wellbore servicing fluids
comprise a drilling fluid, a spacer fluid and a cement slurry,
respectively. In an embodiment, the method further comprises after
placing the at least one third wellbore servicing fluid into the
wellbore, placing into the wellbore a fourth wellbore servicing
fluid comprising a plurality of MEMS sensors having the first type
of RFID tag, wherein the MEMS sensors of the fourth wellbore
servicing fluid are added to a portion of the fourth wellbore
servicing fluid added to the well bore prior to a remainder of the
fourth wellbore servicing fluid, wherein the fourth wellbore
servicing fluid comprises a displacement fluid. In an embodiment,
the first, second, at least one third and fourth wellbore servicing
fluids are pumped down a casing of the wellbore; wherein after
reaching a downhole end of the wellbore, the first, second and at
least one third wellbore servicing fluids are displaced into an
annulus bounded by the wellbore and the casing, wherein when the
fourth wellbore servicing fluid reaches the downhole end of the
wellbore, pumping of the wellbore servicing fluids is discontinued
so as to prevent the fourth wellbore servicing fluid from entering
the annulus. In an embodiment, the positions of the MEMS sensors in
the wellbore are determined using a plurality of data interrogation
units spaced along a length of the wellbore. In an embodiment, the
MEMS sensors are powered by a plurality of power sources spaced
along a length of the wellbore. In an embodiment, the MEMS sensors
are self-powered.
[0268] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of MEMS sensors in a fracture that
is in communication with the wellbore, the MEMS sensors being
configured to measure at least one parameter associated with the
fracture, measuring the at least one parameter associated with the
fracture, transmitting data regarding the at least one parameter
from the MEMS sensors to an exterior of the wellbore, and
processing the data. In an embodiment, the at least one parameter
comprises a temperature, a stress, a strain, a CO.sub.2
concentration, an H.sub.2S concentration, a CH.sub.4 concentration,
a moisture content, a pH, an Na.sup.+ concentration, a K.sup.+
concentration or a concentration. In an embodiment, the data
regarding the at least one parameter is transmitted from the MEMS
sensors to the exterior of the wellbore via a plurality of data
interrogation units spaced along a length of the wellbore. In an
embodiment, the MEMS sensors are powered by a plurality of power
sources spaced along a length of the wellbore. In an embodiment,
the MEMS sensors are self-powered.
[0269] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a cement slurry, placing the cement slurry in an
annulus disposed between a wall of the wellbore and a casing
situated in the wellbore, allowing the cement slurry to cure to
form a cement sheath, determining spatial coordinates of the MEMS
sensors with respect to the casing, mapping planar coordinates of
the MEMS sensors in a plurality of cross-sectional planes spaced
along a length of the wellbore.
[0270] Disclosed herein is a system, comprising a wellbore, a
wellbore servicing fluid situated in the wellbore, the wellbore
servicing fluid comprising a plurality of Micro-Electro-Mechanical
System (MEMS) sensors, a casing situated in the wellbore, a
plurality of centralizers disposed between a wall of the wellbore
and the casing, and spaced along a length of the casing, a
plurality of data interrogation units, each data interrogation unit
being coupled to a separate centralizer, the data interrogation
units being adapted to obtain data from the MEMS sensors, and a
processing unit situated at an exterior of the wellbore and adapted
to receive the data from the data interrogation units and process
the data. In an embodiment, the data interrogation units are molded
to the centralizers. In an embodiment, the data interrogation units
are molded to the centralizers, using a composite resin material.
In an embodiment, the data interrogation units are powered by at
least one turbogenerator situated in the wellbore. In an
embodiment, a turbine in the turbogenerator is driven by at least
one of the wellbore servicing fluid and a production fluid flowing
through the wellbore. In an embodiment, the data interrogation
units are powered by at least one quantum thermoelectric generator
situated in the wellbore. In an embodiment, the at least one
quantum thermoelectric generator is situated in the casing. In an
embodiment, the at least one quantum thermoelectric generator is
situated in production tubing disposed in the wellbore.
[0271] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, a float collar coupled to the
casing proximate to a downhole end of the casing, and a wiper plug
comprising MEMS sensors attached to a downhole end of the wiper
plug, the wiper plug being configured to engage with the float
collar, the MEMS sensors being configured to measure pressure. In
an embodiment, the MEMS sensors are molded to the wiper plug, using
a composite resin material. In an embodiment, the system further
comprises a plurality of data interrogation units attached to an
inner wall of the casing and spaced along a length of the casing.
In an embodiment, the data interrogation units are molded to the
casing, using a composite resin material.
[0272] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, a wiper plug, and a float collar
coupled to the casing proximate to a downhole end of the casing,
the float collar comprising MEMS sensors attached to an uphole end
of the float collar, the uphole end of the float collar being
configured to engage with the wiper plug, the MEMS sensors being
configured to measure pressure. In an embodiment, the MEMS sensors
are molded to the float collar, using a composite resin
material.
[0273] Disclosed herein is a method of servicing a wellbore,
comprising pumping a cement slurry down a casing situated in the
wellbore and up an annulus situated between the casing and a wall
of the wellbore, pumping a wiper plug down the casing, the wiper
plug comprising MEMS sensors at a downhole end of the wiper plug
configured to engage with a float collar, the float collar being
coupled to the casing and situated proximate to a downhole end of
the casing, the MEMS sensors being configured to measure pressure,
discontinuing pumping of the wiper plug when a pressure measured by
the MEMS sensors exceeds a threshold value. In an embodiment, the
MEMS sensors are molded to the wiper plug, using a composite resin
material. In an embodiment, pumping the wiper plug down the casing
comprises pumping a displacement fluid down the casing in back of
the wiper plug, wherein discontinuing pumping of the wiper plug
comprises terminating pumping of the displacement fluid. In an
embodiment, the method further comprises determining a position of
the wiper plug along a length of the casing as the wiper plug is
pumped down the casing. In an embodiment, determining the position
of the wiper plug along the length of the casing comprises
interrogating the MEMS sensors using data interrogation units
attached to an inner wall of the casing and spaced along the length
of the casing.
[0274] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, and a plurality of composite resin
elements molded to an inner wall of the casing and spaced along a
length of the casing, the composite resin elements comprising
Micro-Electro-Mechanical System (MEMS) sensors. In an embodiment,
the system further comprises a wiper plug situated in the casing,
the wiper plug comprising a data interrogation unit configured to
interrogate MEMS sensors in a vicinity of the wiper plug. In an
embodiment, the MEMS sensors are configured to measure a CH.sub.4
concentration in the casing. In an embodiment, the system further
comprises a wellbore servicing fluid situated in the wellbore, the
wellbore servicing fluid comprising a plurality of MEMS sensors,
wherein the MEMS sensors in the wellbore servicing fluid are
configured to measure at least one parameter and transmit data
associated with the at least one parameter from an interior of the
wellbore to an exterior of the wellbore via a data transfer network
consisting of the MEMS sensors in the wellbore servicing fluid and
the MEMS sensors in the composite resin elements, and a processing
unit situated at an exterior of the wellbore and adapted to receive
the data from the MEMS sensors and process the data. In an
embodiment, the composite resin elements are embedded in grooves in
the casing. In an embodiment, the composite resin elements are not
raised with respect to the inner wall of the casing. In an
embodiment, the composite resin elements are mounted flush with the
inner wall of the casing. In an embodiment, the composite resin
elements are situated on casing collars.
[0275] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, and a plurality of composite resin
elements molded to an outer wall of the casing and spaced along a
length of the casing, the composite resin elements comprising
Micro-Electro-Mechanical System (MEMS) sensors. In an embodiment,
the MEMS sensors are configured to measure at least one of a
CH.sub.4 concentration, a CO.sub.2 concentration and an H.sub.2S
concentration in an annulus situated between the casing and a wall
of the wellbore. In an embodiment, the system further comprises a
wellbore servicing fluid situated in the wellbore, the wellbore
servicing fluid comprising a plurality of MEMS sensors, wherein the
MEMS sensors in the wellbore servicing fluid are configured to
measure at least one parameter and transmit data associated with
the at least one parameter from an interior of the wellbore to an
exterior of the wellbore via a data transfer network consisting of
the MEMS sensors in the wellbore servicing fluid and the MEMS
sensors in the composite resin elements, and a processing unit
situated at an exterior of the wellbore and adapted to receive the
data from the MEMS sensors and process the data. In an embodiment,
the composite resin elements are embedded in grooves in the casing.
In an embodiment, the composite resin elements are not raised with
respect to the outer wall of the casing. In an embodiment, the
composite resin elements are mounted flush with the outer wall of
the casing. In an embodiment, the composite resin elements are
situated on casing collars.
[0276] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore servicing fluid, placing the wellbore
servicing fluid in the wellbore, forming a network consisting of
the MEMS sensors in the wellbore servicing fluid and MEMS sensors
situated in composite resin elements, the composite resin elements
being molded to an inner wall of a casing situated in the wellbore
and spaced along a length of the casing, and transmitting data
obtained by the MEMS sensors in the wellbore servicing fluid from
an interior of the wellbore to an exterior of the wellbore via the
network.
[0277] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore servicing fluid, placing the wellbore
servicing fluid in the wellbore, forming a network consisting of
the MEMS sensors in the wellbore servicing fluid and MEMS sensors
situated in composite resin elements, the composite resin elements
being molded to an outer wall of a casing situated in the wellbore
and spaced along a length of the casing, and transmitting data
obtained by the MEMS sensors in the wellbore servicing fluid from
an interior of the wellbore to an exterior of the wellbore via the
network.
[0278] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, a plurality of centralizers
disposed between a wall of the wellbore and the casing and spaced
along a length of the casing, a plurality of composite resin
elements molded to the centralizers, the composite resin elements
comprising Micro-Electro-Mechanical System (MEMS) sensors. In an
embodiment, the MEMS sensors are configured to measure at least one
of a CH.sub.4 concentration, a CO.sub.2 concentration and an
H.sub.2S concentration in an annulus situated between the casing
and a wall of the wellbore. In an embodiment, the system further
comprises a wellbore servicing fluid situated in the wellbore, the
wellbore servicing fluid comprising a plurality of MEMS sensors,
wherein the MEMS sensors in the wellbore servicing fluid are
configured to measure at least one parameter and transmit data
associated with the at least one parameter from an interior of the
wellbore to an exterior of the wellbore via a data transfer network
consisting of the MEMS sensors in the wellbore servicing fluid and
the MEMS sensors in the composite resin elements, and a processing
unit situated at an exterior of the wellbore and adapted to receive
the data from the MEMS sensors and process the data.
[0279] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore servicing fluid, placing the wellbore
servicing fluid in the wellbore, forming a network consisting of
the MEMS sensors in the wellbore servicing fluid and MEMS sensors
situated in composite resin elements, the composite resin elements
being molded to a plurality of centralizers disposed between a wall
of the wellbore and a casing situated in the wellbore, the
centralizers being spaced along a length of the casing, and
transmitting data obtained by the MEMS sensors in the wellbore
servicing fluid from an interior of the wellbore to an exterior of
the wellbore via the network.
[0280] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, and a plastic casing shoe
comprising Micro-Electro-Mechanical System (MEMS) sensors. In an
embodiment, the casing shoe comprises a guide shoe. In an
embodiment, the casing shoe comprises a float shoe.
[0281] Disclosed herein is a system, comprising a wellbore, a
casing situated in the wellbore, a wellbore servicing fluid
situated in the wellbore, the wellbore servicing fluid comprising a
plurality of Micro-Electro-Mechanical System (MEMS) sensors, a
plurality of interrogation/communication units spaced along a
length of the wellbore, wherein each interrogation/communication
unit comprises a radio frequency (RF) transceiver configured to
interrogate the MEMS sensors and receive data from the MEMS sensors
regarding at least one wellbore parameter measured by the MEMS
sensors, at least one acoustic sensor configured to measure at
least one further wellbore parameter, an acoustic transceiver
configured to receive the MEMS sensor data from the RF transceiver
and data from the acoustic sensor regarding the at least one
further wellbore parameter and convert the MEMS sensor data and the
acoustic sensor data into acoustic signals, the acoustic
transceiver comprising an acoustic transmitter configured to
transmit the acoustic signals representing the MEMS sensor data and
the acoustic sensor data on and up the casing to a neighboring
interrogation/communication unit situated uphole from the acoustic
transmitter, and an acoustic receiver configured to receive
acoustic signals representing the MEMS sensor data and the acoustic
sensor data from a neighboring interrogation/communication unit
situated downhole from the acoustic receiver and to send the
acoustic signals representing the MEMS sensor data and the acoustic
sensor data to the acoustic transmitter for further transmission up
the casing, and a processing unit situated at an exterior of the
wellbore, the processing unit being configured to receive the
acoustic signals representing the MEMS sensor data and the acoustic
sensor data and to process the MEMS sensor data and the acoustic
sensor data. In an embodiment, the interrogation/communication
units are powered via a power line running between the units and a
power source situated at an exterior of the wellbore. In an
embodiment, the interrogation/communication units are powered by at
least one turbogenerator situated in the wellbore. In an
embodiment, a turbine in the turbogenerator is driven by at least
one of the wellbore servicing fluid and a production fluid flowing
through the wellbore. In an embodiment, the
interrogation/communication units are powered by at least one
quantum thermoelectric generator situated in the wellbore. In an
embodiment, the at least one quantum thermoelectric generator is
situated in the casing. In an embodiment, the at least one quantum
thermoelectric generator is situated in production tubing disposed
in the wellbore. In an embodiment, the MEMS sensors comprise radio
frequency identification device (RFID) tags.
[0282] Disclosed herein is a method of servicing a wellbore,
comprising placing a wellbore servicing fluid comprising a
plurality of Micro-Electro-Mechanical System (MEMS) sensors in the
wellbore, placing a plurality of acoustic sensors in the wellbore,
obtaining data from the MEMS sensors and data from the acoustic
sensors using a plurality of data interrogation and communication
units spaced along a length of the wellbore, transmitting the data
obtained from the MEMS sensors and the acoustic sensors from an
interior of the wellbore to an exterior of the wellbore using the
casing as an acoustic transmission medium, and processing the data
obtained from the MEMS sensors and the acoustic sensors. In an
embodiment, the method further comprises determining a presence of
a liquid phase and a solid phase of a cement slurry situated in the
wellbore, using the acoustic sensors. In an embodiment, the method
further comprises determining a presence of at least one of cracks
and voids in a cement sheath situated in the wellbore, using the
acoustic sensors. In an embodiment, the method further comprises
detecting a presence of MEMS sensors in the wellbore servicing
fluid, using the acoustic sensors. In an embodiment, the method
further comprises determining a porosity in a formation adjacent to
the wellbore, using the acoustic sensors.
[0283] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in a wellbore composition, flowing the wellbore
composition in the wellbore, and determining one or more fluid flow
properties or characteristics of the wellbore composition from data
provided by the MEMS sensors during the flowing of the wellbore
composition, wherein the fluid flow properties or characteristics
include an indication of laminar and/or turbulent flow of the
wellbore composition, wherein the fluid flow properties or
characteristics include velocity and/or flow rate of the wellbore
composition, and wherein the wellbore composition is circulated in
the wellbore and a fluid flow profile is determined over at least a
portion of the length of the wellbore. In an embodiment, the method
further comprises comparing the fluid flow profile to a theoretical
or design standard for the fluid flow profile, wherein the
comparing is carried out in real-time during the servicing of the
wellbore. In an embodiment, the method further comprises altering
or adjusting one or more operational parameters of the servicing of
the wellbore in response to the comparing in real time, wherein the
altering or adjusting is effective to change a condition of the
wellbore, wherein the condition of the wellbore is a build up of
material on an interior of the wellbore and the altering or
adjusting includes remedial action to reduce an amount of the build
up, wherein the wellbore composition is a drilling fluid and the
build up is a gelled mud or filter cake, wherein the wellbore is
treated to remove at least a portion of the build up, wherein the
treatment to remove at least a portion of the build up comprises
changing a flow rate of the wellbore composition, changing a
characteristic of the wellbore composition, placing an additional
composition in the wellbore to react with the build up or change a
characteristic of the buildup, moving a conduit within the
wellbore, placing a tool downhole to physically contact and
removing the build up, or any combination thereof, wherein the
fluid flow property or characteristic is an actual time of arrival
of at least a portion of the wellbore composition comprising the
MEMS sensors, wherein the actual time of arrival is compared to an
expected time of arrival to determine a condition of the wellbore,
wherein where the actual time of arrival is before the expected
time of arrival indicates a decreased flow path through the
wellbore, wherein the decreased flow path through the wellbore is
attributable at least in part to a build up of gelled mud or filter
cake on an interior of the wellbore, and wherein the flow profile
identifies a location of one or more areas of restricted flow in
the wellbore. In an embodiment, the method further comprises
comparing the location of one or more areas of restricted flow in
the wellbore to a theoretical or design standard for the wellbore,
wherein the one or more areas of restricted fluid flow correspond
to an expected location of a downhole tool or component based upon
the theoretical or design standard for the wellbore, wherein the
downhole tool or component is a casing collar, centralizer, or
spacer. Also disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in at least a portion of a spacer fluid, a sealant
composition, or both, pumping the spacer fluid followed by the
sealant composition into the wellbore, and determining one or more
fluid flow properties or characteristics of the spacer fluid and/or
the cement composition from data provided by the MEMS sensors
during the pumping of the spacer fluid and sealant composition into
the wellbore, wherein the wellbore comprises a casing forming an
annulus with the wellbore wall, wherein the sealant composition is
a cement slurry, and wherein the cement slurry is pumped down the
annulus in a reverse cementing service. In an embodiment, the
method further halts the pumping of the cement slurry in the
wellbore in response to detection of MEMS sensors at a given
location in the wellbore. In an embodiment, the method further
comprises monitoring the wellbore for movement of the MEMS sensors
after the halting of the pumping. In an embodiment, the method
further comprises signaling an operator upon detection of movement
of the MEMS sensors after the halting of the pumping. In an
embodiment, the method further comprises activating at least one
device to prevent flow out of the well upon detection of movement
of the MEMS sensors after the halting of the pumping.
[0284] Disclosed herein is a method of servicing a wellbore,
comprising placing a plurality of Micro-Electro-Mechanical System
(MEMS) sensors in at least a portion of a sealant composition,
placing the sealant composition in an annular space formed between
a casing and the wellbore wall, and monitoring, via the MEMS
sensors, the sealant composition and/or the annular space for a
presence of gas, water, or both, wherein the sealant composition is
a cement slurry and wherein the monitoring is carried out prior to
setting of the cement slurry. In an embodiment, the method further
comprises signaling an operator upon detection of gas and/or water.
In an embodiment, the method further comprises providing a location
in the wellbore corresponding a detection of gas and/or water. In
an embodiment, the method further comprises applying pressure to
the well upon detection of gas and/or water. In an embodiment, the
method further comprises activating at least one device to prevent
flow out of the well upon detection gas and/or water, wherein the
cement slurry is pumped down the annulus in a reverse cementing
service, wherein the cement slurry is pumped down the casing and up
the annulus in a conventional cementing service, wherein the
sealant composition is a cement slurry and wherein the monitoring
is carried out after setting of the cement slurry, and wherein the
monitoring is carried out by running an interrogator tool into the
wellbore at one or more service intervals over the operating life
of the well. In an embodiment, the method further comprises
providing a location in the wellbore corresponding a detection of
gas and/or water. In an embodiment, the method further comprises
assessing the integrity of the casing and/or the cement proximate
the location where gas and/or water is detected. In an embodiment,
the method further comprises performing a remedial action on the
casing and/or the cement proximate the location where gas and/or
water is detected, wherein the remedial action comprises placing
additional sealant composition proximate the location where gas
and/or water is detected, wherein the remedial action comprises
replacing and/or reinforcing the casing proximate the location
where gas and/or water is detected. In an embodiment, the method
further comprises upon detection of gas and/or water, adjusting an
operating condition of the well, wherein the operating condition
comprises temperature, pressure, production rate, length of service
interval, or any combination thereof, wherein adjusting the
operating condition extends an expected service life of the
wellbore. Also disclosed herein is a method of servicing a
wellbore, comprising placing a plurality of
Micro-Electro-Mechanical System (MEMS) sensors in a wellbore
composition, placing the wellbore composition in the wellbore, and
monitoring, via the MEMS sensors, the wellbore and/or the
surrounding formation for movement, wherein the MEMS sensors are in
a sealant composition placed within an annular casing space in the
wellbore and wherein the movement comprises a relative movement
between the sealant composition and the adjacent casing and/or
wellbore wall, wherein at least a portion of the wellbore
composition comprising the MEMS flows into the surrounding
formation and wherein the movement comprises a movement in the
formation. In an embodiment, the method further comprises upon
detection of the movement in the formation, adjusting an operating
condition of the well, wherein the operating condition comprises a
production rate of the wellbore, wherein adjusting the production
rate extends an expected service life of the wellbore, wherein the
gas comprises carbon dioxide, hydrogen sulfide, or combinations
thereof, wherein a corrosive gas is detected, wherein the integrity
of the casing and/or cement is compromised via corrosion and
further comprising performing a remedial action on the casing
and/or the cement proximate the location where corrosion is
present, wherein the wellbore is associated with a carbon dioxide
injection system and wherein the monitoring an undesirable leak or
loss of zonal isolation in the wellbore. In an embodiment, the
method further comprises performing a remedial action on the casing
and/or the cement proximate a location where the leak or loss of
zonal isolation is detected. In an embodiment, the method further
comprises placing carbon dioxide into the wellbore and surrounding
formation to sequester the carbon dioxide.
[0285] Improved methods of monitoring wellbore and/or surround
formation parameters and conditions (e.g., sealant condition) from
inception (e.g., drilling and completion) through the service
lifetime of the wellbore as disclosed herein provide a number of
advantages. Such methods are capable of detecting changes in
parameters in wellbore and/or surrounding formation such as
moisture content, temperature, pH, the concentration of ions (e.g.,
chloride, sodium, and potassium ions), the presence of gas, etc.
Such methods provide this data for monitoring the condition of the
wellbore and/or formation from the initial quality control period
(e.g., during drilling and/or completion of the wellbore, for
example during cementing of the wellbore), through the well's
useful service life, and through its period of deterioration and/or
repair. Such methods are cost efficient and allow determination of
real-time data using sensors capable of functioning without the
need for a direct power source (i.e., passive rather than active
sensors), such that sensor size be minimal to avoid an operational
limitations (for example, small MEMS sensors to maintain sealant
strength and sealant slurry pumpability). The use of MEMS sensors
for determining wellbore and/or formation characteristics or
parameters may also be utilized in methods of pricing a well
servicing treatment, selecting a treatment for the well servicing
operation, and/or monitoring a well servicing treatment during
real-time performance thereof, for example, as described in U.S.
Pat. Pub. No. 2006/0047527 A1, which is incorporated by reference
herein in its entirety.
[0286] While embodiments of the methods have been shown and
described, modifications thereof can be made by one skilled in the
art without departing from the spirit and teachings of the present
disclosure. The embodiments described herein are exemplary only,
and are not intended to be limiting. Many variations and
modifications of the methods disclosed herein are possible and are
within the scope of this disclosure. Where numerical ranges or
limitations are expressly stated, such express ranges or
limitations should be understood to include iterative ranges or
limitations of like magnitude falling within the expressly stated
ranges or limitations (e.g., from about 1 to about 10 includes, 2,
3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). Use
of the term "optionally" with respect to any element of a claim is
intended to mean that the subject element is required, or
alternatively, is not required. Both alternatives are intended to
be within the scope of the claim. Use of broader terms such as
comprises, includes, having, etc. should be understood to provide
support for narrower terms such as consisting of, consisting
essentially of, comprised substantially of, etc.
[0287] Accordingly, the scope of protection is not limited by the
description set out above but is only limited by the claims which
follow, that scope including all equivalents of the subject matter
of the claims. Each and every claim is incorporated into the
specification as an embodiment of the present disclosure. Thus, the
claims are a further description and are an addition to the
embodiments of the present disclosure. The discussion of a
reference herein is not an admission that it is prior art to the
present disclosure, especially any reference that may have a
publication date after the priority date of this application. The
disclosures of all patents, patent applications, and publications
cited herein are hereby incorporated by reference, to the extent
that they provide exemplary, procedural or other details
supplementary to those set forth herein.
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